Abstract:
An apparatus for coupling with a mating coupling module to facilitate the joining of two disjoined structures without requiring precise alignment between the disjoined structures during the coupling of them may include a rotating drive mechanism, a hollow cylindrical body operatively connected to the rotating drive mechanism, wherein the hollow cylindrical body has at least one internal spiral channel, and at least one connector claw positioned within the hollow cylindrical body and guided by the internal spiral channel, wherein the at least one connector claw is configured to extend outwardly from the coupling module to engage the mating coupling module when brought in close proximity but not necessarily in precise alignment with the mating coupling module.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority under 35 U.S.C. §119(e) from co-pending, commonly owned U.S. provisional patent application, Ser. No. 60/744,483, filed on Apr. 7, 2006, entitled “Compliant, Low Profile, Non-Protruding, and Genderless Docking System for Robotic Modules.” The entire content of this provisional application is incorporated herein by reference. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH  
       [0002]     Portions of this invention may have been made with government support under NASA Grant SuperBot Project, awarded by the United States Government. The government may have certain rights in the invention. 
     
    
     BACKGROUND  
       [0003]     Docking between multiple disjointed structures can be a problem that occurs in engineering systems that must dynamically change their structures for various purposes. Human-operated docking is widely seen in daily life, and can be as simple as changing a blade in a razor or as complex as docking one spacecraft to another.  
         [0004]     Autonomous docking, however, may have the ability to enable all reconfigurable actions, and may be able to perform frequent docking/undocking routines and in different system configurations and structures. Further, autonomous docking may need to foolproof and support all of the interconnection needs of the system—from structural load bearing to communications and power sharing.  
         [0005]     Among applications of autonomous docking, one that may benefit from autonomous docking may be the self-reconfigurable or metamorphic robot. Such robots may be made of many autonomous coupling modules that self-rearrange their connections to change the robot&#39;s morphology (e.g., shape and size) in order to meet environmental and other demands of a given task. Such robots may be useful in applications that benefit from or require the use of robots with different topologies. A metamorphic robot could be a “crab” to climb over rubble and then smoothly morph to a “snake” to slither down between the stones to locate a person or some artifact. It may become a ball to roll down a hill, or transform a leg into a gripper to perform a grasping operation. Coupling modules are usually interconnected to make a chain or tree of modules, but rings and lattices are supported also. The task of autonomous docking in these robots may be intricate and challenging. A reliable solution might be applied to almost any docking domain.  
         [0006]     Indeed, autonomous docking is a long-standing and challenging problem for self-reconfigurable robots. The challenge lies in the fact that autonomous docking may be the only ability that enables all reconfigurable actions, and may need to be performed frequently and in different system configurations. Docking may need to be foolproof and support all of the interconnection needs of the system—from structural load bearing to communications and power sharing. Such docking systems may involve positioning the various modules correctly, then making a connection that must support as many modalities as needed in a particular application, and work in many, sometimes wet, dirty, and hostile environments. The problem of interconnection and interfacing may get much worse as the number of modalities involved increases. Furthermore, the components may need to make and break both multi-modal electrical and mechanical connections, in spite of being repeatedly connected and disconnected.  
         [0007]     Autonomous docking may be critical to the success of metamorphic robots. Without a reliable solution to the problem, the true advantages of metamorphic robots may not be delivered to real-world applications and may remain a mathematical exercise exciting only scientific curiosity. After nearly ten years of research by the international community, autonomous docking is commonly believed to be among the most challenging problems in self-reconfigurable robots.  
         [0008]     Accordingly, there is a need for systems and methods that can couple two disjointed structures and, additionally, eliminating the need for human-operation.  
       SUMMARY  
       [0009]     One aspect of an apparatus for coupling with a mating coupling module is disclosed. The apparatus for coupling with a mating coupling module to facilitate the joining of two disjoined structures without requiring precise alignment between the disjoined structures during the coupling of them may include a rotating drive mechanism, a hollow cylindrical body operatively connected to the rotating drive mechanism, wherein the hollow cylindrical body has at least one internal spiral channel, and at least one connector claw positioned within the hollow cylindrical body and guided by the internal spiral channel, wherein the at least one connector claw is configured to extend outwardly from the coupling module to engage the mating coupling module when brought in close proximity but not necessarily in precise alignment with the mating coupling module.  
         [0010]     Another aspect of an apparatus for coupling with a mating coupling module is disclosed. The apparatus for coupling to a mating coupling module to facilitate the joining of two disjoined structures without requiring precise alignment between the disjoined structures during the coupling of them may include a rotating drive mechanism, and a first connector claw operatively connected to the rotating drive mechanism, wherein the first connector claw outwardly extends so as to allow the first connector claw to engage a second connector claw of the mating coupling module and draw the coupling module together with the mating coupling module.  
         [0011]     One aspect of a method of coupling two disjointed structures is also disclosed. The method of coupling two disjointed structures without requiring precise alignment between the two disjointed structures during the coupling of them may include rotating a first connector claw operatively connected with a first disjoined structure, extending the first connector claw outwardly toward a second connector claw, wherein the second connector claw is operatively connected to a second disjoined structure, moving the first and second connector claws to a close proximity between each other but not necessarily in precise alignment, and engaging the first connector claw with the second connector claw so as to draw the second disjoined structure together with the first disjoined structure. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     Aspects of the present invention are illustrated by way of example, and not by way of limitation, in the accompanying drawings wherein:  
         [0013]      FIG. 1  is a perspective illustration of an embodiment of a coupling module in a retracted position.  
         [0014]      FIG. 2  is a perspective illustration of a coupling module in a retracted position with the top portion removed, thereby exposing the internal components of the coupling module.  
         [0015]      FIG. 3  is a perspective illustration of the layered components that rotate about a main shaft.  
         [0016]      FIG. 4  is a perspective illustration of a center shaft sleeve as it relates to a base portion having a fixed main shaft.  
         [0017]      FIG. 5  is a perspective illustration of a pin drive gear.  
         [0018]      FIG. 6  is a perspective illustration of a guiding pin mechanism.  
         [0019]      FIG. 7  is a perspective illustration of an embodiment of a coupling module in an extended position.  
         [0020]      FIG. 8  is a perspective illustration of an embodiment of a coupling module in an extended position and engaged with the connector claws of a mating coupling module.  
         [0021]      FIG. 9  is a perspective illustration of the layered components that together comprise a coupling module.  
         [0022]      FIGS. 10   a - 10   d  illustrate consecutive positions that draw two disjointed connector plates close together. 
     
    
     DETAILED DESCRIPTION  
       [0023]     The detailed description set forth below in connection with the appended drawings are intended as a description of various embodiments and is not indeed to represent the only embodiment in which it may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding, however, it will be apparent to those skilled in the art that what is disclosed may be practiced without these specific details. In some instances, well-known structures and components are shown in basic diagram form in order to avoid obscuring the concepts.  
         [0024]     The various concepts described throughout this disclosure may be applied to any group of coupling modules. The coupling modules may be attached to any robot or other suitable disjointed structure. In the following detailed description, these concepts will be described in the context of a coupling module and a mating coupling module configured to independently engage or disengage with each other to comprise a fully autonomous docking system. The autonomous docking system may include several unique features, including high compliance, low profile, independent docking and undocking ability, being non-protruding, and allows genderless interconnection. High compliance may be accomplished since the coupling module and mating coupling module may be able to dock under relatively high positioning errors in omni-directions. Further, due to the coupling module design of having minimal distance between top and base portions, the several coupling module units may be installed on multiple faces of a robot module (or any other docking surface) without seriously enlarging the overall robot volume. This low profile may be especially important when docking has to be performed in tight regions where there is not much space for maneuverability.  
         [0025]     The independent docking and undocking feature may be capable of being carried out by each coupling module so as to disengage with the coupling mating module even if the mating module malfunctions. Also, when the coupling module is placed in non-operational or passive mode, there may be no protrusions from its surface, therefore, it may not limit the motion of the robot on which it is installed. And unlike most docking pairs, the coupling module may not have fixed male and female configurations. A pair of coupling and mating coupling modules may be identical, however, upon docking one of the modules protrudes its rotating claws and enters the mating module.  
         [0026]      FIG. 1  is a perspective illustration of an embodiment of a coupling module  100  in a retracted position. In the initial state, the connector plate  106  having connector claws  108  may be fully recessed or retracted within a hollow cylindrical body  110 . The hollow cylindrical body may have one or more internal spiral channels  112  which may assist in guiding the connector plate  106  up the hollow cylindrical body  110  once the coupling module  100  attempts to engage a mating coupling module (not shown).  
         [0027]     Further, the coupling module  100  may have a top portion  102  which exposes at least connector claws  108  to enable engaging with a mating docking module when the connector claws  108  are extracted or protruded. The top portion  102  may be connected to a base portion  104 . The base portion  104  may have a fixed main shaft substantially center to the base portion  104  in order to provide focal center whereupon all rotating components revolve. A center shaft sleeve  116  may be connected to the fixed main shaft of the base portion  104 . The connector plate  106  may rotate in unison with the center shaft sleeve  116  but only until the connector plate  106  reaches the maximum extending range. Once the connector plate  106  reaches the maximum extending range, the connector plate  106  may abut a top flange of the center shaft sleeve  116 . Also, the center shaft sleeve  116  may have a vertical external channel and may guide the connector plate  106  from within the connector plate&#39;s  106  center ring.  
         [0028]      FIG. 2  is a perspective illustration of a coupling module  100  in a retracted position with the top portion  102  removed, thereby exposing the internal components of the coupling module  100 . The driving mechanism  202  may be configured to rotate a primary gear  204 . The driving mechanism may be a motor or any device that may provide forward and reverse rotational movement to the primary gear  204 . In this illustrative embodiment, the driving mechanism  202  transfers its rotating force to the primary gear  204  through a series of beveled gears and a warm gear. However, one of ordinary skill in the art can appreciate that the driving mechanism  202  could just as readily be oriented so as to not require the use of any gear or oriented so as to require the use of different gears. For example, the use of an additional shaft, which is in perpendicular position to the driving mechanism  202  axis, is merely to create a compact design. Otherwise, the driving mechanism  202  may directly drive a warm gear without the need for additional bevel gears.  
         [0029]     The primary gear  204  may be connected to the hollow cylindrical body  110 . Thus, as the primary gear  204  rotates, the hollow cylindrical body  110  may rotate in unison with the primary gear  204 . The pin drive gear  206  may be connected with the hollow cylindrical body  110  by detent mechanism. A detent mechanism, as used herein, is a mechanical arrangement used to hold a moving part in a temporarily fixed position relative to another part, i.e., one part rotates within the other. Here, the pin drive gear  206  may rotate about the main shaft to drive the guide or guiding pins  114  vertically perpendicular to the connector plate  106 . Once the guiding pins  114  are fully extended, the detents along the inner circumference of the pin drive gear  206  release, thus, the pin drive gear may remain stationary while the hollow cylindrical body  110  continues to rotate.  
         [0030]      FIG. 3  is a perspective illustration of the layered components that rotate about a main shaft. The connector plate  106  may have one or more connector claws  108  positioned so as to have the connector plate&#39;s  106  external circumference guided by the internal spiral channels  112  of the hollow cylindrical body  110 . The connector plate&#39;s  106  internal circumference may be guided by the one or more vertical external channels  302  of the center shaft sleeve  116 . The internal spiral channels  112  of the hollow cylindrical body  110  may push the connector claws  108  and connector plate  106  forward, while the substantially vertical channels of the center shaft sleeve  116  may prevent the connector plate  106  from turning with the hollow cylindrical body  110 .  
         [0031]      FIG. 4  is a perspective illustration of a center shaft sleeve  116  as it relates to a base portion  104  having a fixed main shaft. The center shaft sleeve  116  may be connected by rivet, pin, nail, bolt, or any other type of fastener that would freely enable the rotational movement of the connector plate  106 . The base portion  104  having a fixed main shaft may use a detent mechanism so as to prevent the center shaft sleeve  116  from rotating while the connector plate  106  rises up the hollow cylindrical body  110 . However, once the connector plate  106  reaches the top flange of the center shaft sleeve  116 , and thereby attaining the maximum extending range of the connector claws  108 , the center shaft sleeve  116 , the connector plate  106 , the hollow cylindrical body  110 , and the primary gear may all rotate in unison to engage a coupling mating module.  
         [0032]      FIG. 5  is a perspective illustration of a pin drive gear  206 . The pin drive gear  206  may be connected to the hollow cylindrical body  110  by means of the detents  502  that engage depressions around the outer surface of the hollow cylindrical body  110 . The detent mechanism  502  may be configured to release once the guiding pins  114  are fully extended.  
         [0033]      FIG. 6  is a perspective illustration of a guiding pin  114  mechanism. As the primary gear  204  may be rotated by the driving mechanism  202 , the primary gear  204  may rotate the hollow cylindrical body  110 , which in turn may rotate the pin drive gear  206 . As the pin drive gear  206  rotates, all pin screw gears  602  may rotate. The pin screw gears  602  may raise the guiding pin  114  by spring mechanism. The spring mechanism may prevent the guiding pin  114  from jamming the pin drive gear  206  and may allow the guiding pin  114  to be forced flush to the top portion  102  if the guiding pin  114  meets external resistance. The guiding pin  114  may have a point that is substantially spherical to facilitate insertion into a coupling mating module&#39;s receiving guiding pin cavity.  
         [0034]      FIG. 7  is a perspective illustration of an embodiment of a coupling module in an extended position. Once the drive mechanism  202  has caused the connector plate  106  to reach its maximum extending range, the connector plate  106  may be substantially flush with the plane of the top portion  102 . The center shaft sleeve&#39;s  116  flange may prevent the connector plate  106  from extending any further. At this point the turning force of the driving mechanism  202  may be transferred to the center shaft sleeve  116  through the connector plate  106 . This force may defeat the stopping force of the spring loaded balls of the main shaft and hence, the shaft sleeve  116 , the connector plate  106 , and the hollow cylindrical body  110  may turn in unison. At the fully extended position, the guiding posts  114  may also be fully extended.  
         [0035]      FIG. 8  is a perspective illustration of an embodiment of a coupling module  100  in an extended position and engaged with the connector claws  108  of a mating coupling module. A connector plate  106   b,  after having been fully extended, may engage the connector plate  106   a  of a mating coupling module. As the protruded connector claws  108  of the connector plate  106  rotate and enter the hollow cylindrical body  110  of the coupling mating module (not shown), the two claws sets  108   a  and  108   b  may interlock and docking may be completed. Increased motor current may signal the end of motion range. Reverse action of the driving mechanism  202  may unlock the connector plate  106  and retract it inward into the hollow cylindrical body  110 . The retracting step may also retract the guiding pins  114  by reversing the pin drive gear  206 .  
         [0036]      FIG. 9  is a perspective illustration of the layered components that together comprise a coupling module. One of ordinary skill in the art may appreciate that the layered components may be interchanged and/or substituted with different components achieving the substantially equal result without deviating from the teachings of this disclosure.  
         [0037]      FIGS. 10   a - 10   d  illustrate consecutive positions that draw two disjointed connector plates  106  close together. In  FIG. 10   a,  a large axial deviation between one connector plate  106  and the connector plate  106  of a coupling mating module exists. The axial deviation subsequently narrows as the rotating connector plate  106  is drawn close to the stationary connector plate  106 , as shown in  FIGS. 10   b - 10   c.  The process of narrowing the axial deviation may ultimately result in the full concentric alignment of both connector plates  106  once the fully engaged position has been reached, as shown in  FIG. 10   d.  This is an example of the self-centering property of the two connector plates  106 . The connector plates  106  may be drawn together by the tapered edges of the connector claws  108 . Thus, when the connector claws  108  are run against the mating coupling module&#39;s  100  connector claw  108  edges of the section vertical to the connector plate  106 , the connector plates  106  may slide and position themselves such that the two connector plates  106  become co-centrical.  
         [0038]     The previous description is provided to enable any person skilled in the art to practice the various embodiments described herein. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments. Thus, the claims are not intended to be limited to the embodiments shown herein, but is to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” All structural and functional equivalents to the elements of the various embodiments described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. § 112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.”