Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D57/00—Vehicles characterised by having other propulsion or other ground- engaging means than wheels or endless track, alone or in addition to wheels or endless track
  • B62D57/02—Vehicles characterised by having other propulsion or other ground- engaging means than wheels or endless track, alone or in addition to wheels or endless track with ground-engaging propulsion means, e.g. walking members
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D57/00—Vehicles characterised by having other propulsion or other ground- engaging means than wheels or endless track, alone or in addition to wheels or endless track
  • B62D57/02—Vehicles characterised by having other propulsion or other ground- engaging means than wheels or endless track, alone or in addition to wheels or endless track with ground-engaging propulsion means, e.g. walking members
  • B62D57/024—Vehicles characterised by having other propulsion or other ground- engaging means than wheels or endless track, alone or in addition to wheels or endless track with ground-engaging propulsion means, e.g. walking members specially adapted for moving on inclined or vertical surfaces

Definitions

• the invention relates to a miniature robotic device, more specifically a miniature crawler and a miniature inspector using the same, and a method for operating a miniature robotic device, more specifically a miniature crawler and a miniature inspector using the same.
• the miniature crawlers are having relatively big sizes and cannot crawl inside of air gap which is smaller than for example 10 mm.
• Many of the existing miniature crawlers use wheel or truck as a drive mechanism.
• Additionally constructions of known miniature crawlers are rigid which also limits the size of air gap in which the robotic device can crawl in. This situation is particularly relevant in the case of other potential application of the crawlers like for example crawling into tubes or pipes.
• the present invention provides a miniature crawler to crawl on surface of an object, comprising: a chain having at least one driving unit and at least one of the at least one driving unit including a piezoelectric element therein; and two anchoring elements connected with two ends of the chain, each of which is configured to be releasably fixed onto the surface.
• the present invention provides a miniature crawler to crawl on surface of an object, comprising: a chain having at least two driving units connected in series and at least a part of the driving units including piezoelectric element therein; and two anchoring elements connected with two ends of the chain, each of which is configured to be releasably fixed onto the surface.
• At least a part of the at least two driving units includes a mechanical amplifier and a piezoelectric element connected with the mechanical amplifier.
• the mechanical amplifier is flexible and in the shape of hexagon, and the piezoelectric element is connected with two opposite sides of the hexagon.
• the mechanical amplifier is made by plastics using rapid prototyping technology.
• the driving units are flexibly connected with each other, such as hinged with each other.
• the anchoring elements are electric magnetic elements when the surface and/or the object are/is ferromagnetic.
• the anchoring elements are selected from suckers, controlled friction elements or electro-adhesion elements.
• the miniature crawler further comprises a second chain crossed with the chain and two second anchoring elements connected with two ends of the second chain, each of which is configured to be releasably fixed onto the surface, the second chain has at least two driving units connected in series and at least a part of the driving units include piezoelectric element therein.
• the chain and the second chain are perpendicular with each other, and optionally may have one common driving unit at the crossing point.
• the crawler is used to pass through a gap between a stator and a rotor of a generator.
• the mechanical amplifier is made of steel, aluminum, or composite.
• the present invention further provides a miniature inspector, including a miniature crawler as described above and an inspecting device attached onto the crawler.
• the inspecting device is a high resolution camera, ultrasonic transducer, magnetic field sensors, or mechanical actuator.
• a method for operating a miniature crawler as described herein is provided.
• the method may be accomplished with a miniature crawler as described herein.
• the miniature crawler may include a piezoelectric element and a first and a second anchoring element.
• the method includes the steps of powering the first anchoring element so that it sticks on the surface; prolonging the piezoelectric element by powering it; powering the second anchoring element so that it sticks onto the surface; and releasing the first anchoring element.
• the invention is also directed to an apparatus for carrying out the disclosed methods and including apparatus parts for performing each described method steps. These method steps may be performed by way of hardware components, a computer programmed by appropriate software, by any combination of the two or in any other manner. Furthermore, the invention is also directed to methods by which the described apparatus operates. It includes method steps for carrying out every function of the apparatus.
• FIG. 1 shows a circumstance where a miniature crawler is used, which serves only as an exemplary application of the present invention
• FIG. 2 shows a schematic structure of a crawler according to an embodiment of the present invention
• FIG. 3 shows a schematic diagram illustrating the moving mechanism of the crawler according to an embodiment of the present invention
• FIG. 4 shows a schematic structure of a crawler according to another embodiment of the present invention.
• FIG. 5 shows a perspective view of the crawler shown in Fig. 4;
• FIG. 6 shows a schematic diagram illustrating the amplifying mechanism of a mechanical amplifier according to an embodiment of the present invention
• FIG. 7 shows a schematic three dimensional illustration of the mechanical amplifier according to an embodiment of the present invention.
• FIG. 8 shows a schematic structure of a crawler according to a further embodiment of the present invention.
• FIG. 1 shows a circumstance where a miniature crawler is used, which serves only as an exemplary application of the present invention.
• a miniature crawler As shown in Fig. 1, there is a gap 4 between the rotor 3 and stator 2 of a generator which needs to be inspected periodically.
• conventional means are not applicable unless the generator is dissembled.
• the gap is very small such as less than 10mm, there is a strong need for such a miniature crawler 1 which can pass through the radial air gap 4 between the rotor 3 and the stator 2.
• Fig. 2 shows a schematic structure of a miniature crawler according to one embodiment of the present invention.
• the miniature crawler includes a chain having a plurality of piezoelectric elements 15 (as a driving unit as defined in the below) connected in series and two anchoring elements 13 attached respectively to the two ends 14 of the chain.
• the piezoelectric elements 15 are flexibly connected with each other so that the crawler can conform to a curving surface along which the crawler is moving.
• the piezoelectric elements 15 are hinged with each other so that the piezoelectric element 15 is rotatable around an axis parallel with the transversal direction of the piezoelectric element 15.
• the flexible crawler will well fit the need where the gap to be passed through is curving with a small bending radius.
• each of the anchoring elements 13 is an electric magnetic element such as electromagnet or magnetic coil which can stick onto the surface along which the crawler is moving when it is powered and can be released from the surface when the power is off.
• the electric magnetic elements can only be used when the surface along which the crawler is moving or the object under/of the surface (hereinafter collectively referred to as the object of the surface and it should be understood that both are within the scope of the present invention) is ferromagnetic.
• Other ways may also be used such as sucker, controlled friction or electro-adhesion.
• the anchoring elements will be similarly used and will not be repeatedly described for each embodiment.
• Fig. 3 shows a schematic diagram illustrating the moving mechanism of the crawler according to an embodiment of the present invention.
• arrow 16 indicates the direction along which the crawler is moving.
• the crawler is put onto the surface to be moved along.
• the anchoring element 13 at left side is powered so that it can stick onto the surface.
• step S3 by powering the piezoelectric elements 15, it will be prolonged in its longitudinal direction when an external electric field is applied thereto, and thus the anchoring element 13 at right side will move rightwards since the anchoring element 13 at left side is sticking onto the surface.
• step S4 the anchoring element 13 at right side is powered so that it can stick onto the surface while the anchoring element 13 at left side is released by removing the electric field applied thereto.
• step S5 the electric field applied onto the piezoelectric elements 15 is removed and thus the piezoelectric elements 15 will be shortened in its longitudinal direction, and then the anchoring element 13 at left side will move rightwards since it has been released while the anchoring element 13 at right side is sticking onto the surface.
• the crawler Comparing the position of the crawler at SI with the position at S5, the crawler has been moved rightwards. By repeating the foregoing process, the crawler can move rightwards to a further extent. By reversing the order of powering the anchoring elements 13 at left side and right side, the crawler can move leftwards.
• the piezoelectric element 15 can be powered by a high frequency electric signal, such as at 1000 Hz, and thus the actual moving distance of the crawler will be visible even though a single deformation of the piezoelectric element 15 may not be visible.
• the crawler includes a plurality of piezoelectric elements 15, not all of them need to be powered at same time, and the circumstance where only part of them are powered at same time is also within the scope of the present invention, although it will not be specifically pointed out every time.
• the piezoelectric element 15 will be prolonged in its longitudinal direction when an external electric field is applied thereto.
• the present invention is also applicable where the piezoelectric element 15 will be shortened in its longitudinal direction when an external electric field is applied thereto, and only the moving direction of the crawler or the order of powering the anchoring elements will be changed.
• Figs. 4 and 5 show schematic structure of a crawler according to another embodiment of the present invention.
• the miniature crawler includes a chain including a plurality of driving units 12 connected in series and two anchoring elements 13 attached respectively to the two ends 14 of the connected driving units 12.
• Each driving unit 12 includes a mechanical amplifier 21 and a piezoelectric element 15 connected therewith.
• the driving units 12 are flexibly connected with each other so that the crawler can conform to a curving surface along which the crawler is moving.
• the driving units 12 are hinged with each other so that it is rotatable around an axis perpendicular with the longitudinal direction of the crawler.
• each of the anchoring elements 13 is electric magnetic elements which can stick onto the surface along which the crawler is moving when it is powered and can be released from the surface when the power is off.
• FIG. 6 shows a schematic diagram illustrating the amplifying mechanism of a mechanical amplifier according to an embodiment of the present invention.
• the amplifier is flexible and in shape of a hexagon, and the piezoelectric element 15 connected therewith is located between two opposite sides of the hexagon, thus leaving two jointed sides at both transversal sides of the piezoelectric element 15.
• the piezoelectric element 15 is in its original position between two opposite sides 211 and 212, and two jointed sides 213 and 214 are located at left side of the piezoelectric element 15 while the two jointed sides 215 and 216 are located at right side of the piezoelectric element 15.
• the piezoelectric element 15 will be prolonged in its longitudinal direction by applying electrical field thereon, and thus the two sides 211 and 212 will move away from each other and the jointed sides 213 and 214 and the jointed sides 215 and 216 will respectively buckle inward, reducing the transversal size SI of the hexagon.
• the reduced size of the hexagon could be, for example 3mm, triple of the deformation amplitude of the piezoelectric element 15.
• the extent of amplifying could be different and will not be described in detail here. Since a single move of piezoelectric element is small and may not well serve the need of a quick move even with the high frequency electric signal, this embodiment provides an even advantageous solution.
• the crawler shown in Fig. 5 will move leftwards, but it should be understood that the crawler can move rightwards by various other ways, such as by reversing the order of powering the anchoring elements at left side and right side.
• Fig. 7 shows a schematic three dimensional illustration of the mechanical amplifier according to an embodiment of the present invention.
• the mechanical amplifier 21 is a three dimensional hexagon having a length L, width W, and height H.
• the mechanical amplifier 21 can be made of various materials, such as plastics, steel, aluminum or composite, and can be produced by rapid prototyping (RP) technology which enables quick and cheap adjustment to macro scale shape of the mechanical amplifier 21.
• RP rapid prototyping
• the height H could be about 3mm only, while the length L and width W could be about 5.5 mm and 3.5 mm respectively, which means the height of the miniature crawler could be as small as 3mm, and thus satisfy the application need where the gap to be passed through is quite small.
• the mechanical amplifier 21 can be made even smaller.
• the crawler in Fig. 2 includes a plurality of piezoelectric elements 15 while the crawler in Fig. 4 includes a plurality of driving units 12 with mechanical amplifier 21,
• the solution mixing the piezoelectric elements with driving units having mechanical amplifier in the chain is also within the scope of the present invention, and the solution mixing the piezoelectric elements and/or the driving units having mechanical amplifier with other elements in the chain of connection is also within the scope of the present invention, although it will not be specifically pointed out every time, and hereinafter the piezoelectric element 15 in Fig. 2, the driving unit 12 including the piezoelectric element and the mechanical amplifier in Fig. 4, and other elements in the chain of connection are collectively referred to as driving unit(s).
• Fig. 8 shows a schematic structure of a crawler according to a further embodiment of the present invention.
• the crawler can only move in one dimension, i.e. in the direction of right and left shown in the drawing.
• two one-dimensional crawlers as described above are crossed with each other and optionally may have one common driving unit at the crossing point, and a payload 17 is located at the crossing point.
• the payload 17 can be moved in either right-and-left direction or up-and-down direction.
• the payload 17 can move in right and left direction with the help of the left and right anchoring elements 13, and the payload 17 can move in up and down direction with the help of top and bottom anchoring elements 13.
• the two directions do not have to be perpendicular with each other.
• the above crawler can carry a high resolution camera, ultrasonic transducer, magnetic field sensors and/or other sensors to provide a clear view of the stator core laminations, stator wedges, field wedges and inboard ends of the retaining rings. Further, the above crawler can carry mechanical actuators to conduct maintenance work or the like.
• the crawler as described can certainly be applied to circumstances where other functions are required such as to make repair or maintain an object.
• the present application uses the term “inspector” or “inspecting device” to cover all these situations and shall not be construed as device having inspecting function only.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)

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Citations (6)

• 2012
  • 2012-12-21 CN CN201210563205.1A patent/CN103879468A/zh active Pending
• 2013
  • 2013-02-20 WO PCT/EP2013/053341 patent/WO2014095091A1/en active Application Filing

Patent Citations (6)

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