Abstract:
Autonomous cooperative units working together to solve diagnostics, monitoring, surveillance, reconfiguration, and control problems may be organized into clusters and cluster associations, for example along the lines of a particular distribution system for water, power or the like. The clusters allow controlled communication among agents within different services and support the coordinated diagnostics, reconfiguration, and control across coupled systems.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. provisional application 60/563,247 filed Apr. 15, 2004 hereby incorporated by reference. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to computerized automation systems and in particular to automation systems employing autonomous cooperating units (“ACU”).  
         [0003]     Distribution systems, for example, those found in a modem warship, distribute materials such as fuel, ballast water, fire water, chilled water and compressed air, fresh air, as well as electrical power, to different points in the ship and to various devices, machines, computers, and other electronic equipment. Materials, air, and power flow through complex networks of conduits or wiring that form branches between nodes such as pumps, generators, valves, switches, sensors and the like.  
         [0004]     Under changing demand, disturbances, or disruption to the networks, the networks may be reconfigured, taking advantage of redundancy built into the nodes and branches of the distribution system and the priority of users. For example, in a warship, chilled water provides cooling for critical electrical components and machines such as radar, communications equipment, and armaments, as well as cooling for crew quarters and work areas. Should the network be damaged through the loss of a section of pipe or a pump failure or water chiller failure, autonomous agents may collaborate to confirm the type and extent of damage or failure. Further collaboration may result in control valves being adjusted to minimize water loss or reduce consequential damage. Subsequent collaboration may establish routing plans to route chilled water around damaged pipe sections to critical heat loads and re-allocating cooling capacity from less critical needs to critical ship systems. If sufficient chilled water cannot be obtained, further, more drastic reconfiguration options may be exercised such as violating the segregation of chilled water between port and starboard sides of the ship.  
         [0005]     Effectively controlling a complex chilled water system with a commercial programmable logic controller (PLC) is difficult, requiring the anticipation and preparation of pre-programmed responses for each of a large number of possible combinations of water demand, system disturbances, and network component availability or failure, according to changing strategic goals. U.S. application Ser. No. 10/737,384 filed Dec. 16, 2003, hereby incorporated by reference and assigned to the same assignee as the present invention, describes a control system for chilled water or other materials in which the various nodes and branches of the distribution network are associated with autonomous cooperating units (“ACUs”). The ACUs independently provide reasoning about component health or condition and electrical control or sensing of a different component of the distribution network, for example, a pump, pipe or valve. Together, the ACUs receive generalized instructions for the delivery of chilled water and then organize themselves, according to a bidding process, to deliver the water as required. Because the bidding process reflects the current state of the distribution system (e.g., ACUs don&#39;t bid for tasks if their associated components are damaged) an efficient solution may be obtained even when the distribution network is subject to unanticipated damage.  
         [0006]     The ACU architecture can provide better control over a distribution system than manual systems or conventional centralized control systems can.  
       SUMMARY OF THE INVENTION  
       [0007]     The present inventors have recognized that a given distribution system is ordinarily operating in parallel with other distribution systems and operational systems (e.g. ship propulsion) that inevitably both augment and compete with the given distribution systems for limited resources. Improved control of a distribution system may be possible by cross communication among parallel distribution systems enabled by the versatility, speed, and scalability of the ACU architecture.  
         [0008]     For example, by allowing communication between a chilled water distribution system and the electrical power distribution, the chilled water system can invoke power resources in bidding, for example, by bidding for additional power for a power degraded pump. The degraded pump may have a worn impellor requiring the motor to run at a much higher speed to maintain the required hydraulic head or flow rate. Given that this is a viable operating scenario, the motor-pump control agent may request additional power from the associate owner control agent in order to realize the new, higher pump speed operating scenario.  
         [0009]     The significantly increased complexity of such a cross-connected or coupled system is managed through the use of a cluster structure that flexibly and dynamically controls the degree to which such cross-communication between and among agents in different ship services occurs. By changing the cluster structure, flexible trade-offs are achieved between, on the one hand, rapid and efficient organization of a limited number of autonomous cooperative units and, on the other hand, highly sophisticated control requiring communication of far larger numbers of autonomous cooperative units.  
         [0010]     Specifically then, the present invention provides an autonomous control system for managing at least two different distribution services, each distribution service providing distribution nodes and branches. The at least two different distribution services are coupled in the sense that a change in one service may impact the other service or an alteration in one service is required to realize a change in the other service. The autonomous control system includes a plurality of autonomous cooperative units, at least some of which are associated with nodes and branches of each distribution service. Each autonomous cooperative unit is programmed to cooperatively implement a job command by a bidding process among autonomous cooperative units associated with a predefined cluster related to one of the distribution services. At least one of the autonomous cooperative units is programmed to cooperatively implement the job command by a bidding process among autonomous cooperative units associated with a predefined cluster related to at least two of the distribution services.  
         [0011]     Thus, it is one objective of at least one embodiment of the invention to provide a more sophisticated control of distribution services by communication with coupled distribution services.  
         [0012]     The distribution services may include the distribution of a physical material, for example, compressed air, chilled water, fuel, chilled air and ballast water.  
         [0013]     Thus it is another objective of at least one embodiment of the invention to provide a system that is well suited for distribution of utilities and the like, for example on a warship, in an aircraft, or in a municipality.  
         [0014]     The nodes may be motor-pumps, tanks, chillers, heaters, valves, and the branches pipes.  
         [0015]     Thus it is another objective of at least one embodiment of the invention to provide a distribution control system that works with a wide variety of distribution services.  
         [0016]     The distribution service may include the distribution of electrical power, in which case the nodes may be switches, power controllers, power sources (e.g. generators or batteries) and power sinks (e.g. motors or electrical equipment) and the branches wire.  
         [0017]     It is thus another objective of at least one embodiment of the invention to provide a control system that allows for intercommunication between a distributed utility and the power which services the nodes and branches of that utility.  
         [0018]     The autonomous cooperative units that are associated with at least two of the distribution services may not be associated with nodes or branches of either distribution service.)  
         [0019]     Thus it is another objective of at least one embodiment of the invention to allow for a hierarchical communication between distribution services using agents dedicated solely to that intercommunication. Such an agent is referred to as a cluster agent.  
         [0020]     The system may include a plurality of directory facilitators communicating with the multiple autonomous cooperative units, wherein the autonomous cooperative units communicate in the bidding process among autonomous cooperative units of a predefined cluster defined by the directory facilitator.  
         [0021]     Thus it is an object of at least one embodiment of the invention to provide for a mechanism to flexibly change the clusters on a dynamic basis.  
         [0022]     It is another object of at least one embodiment of the invention to manage the communication among agents according to desired trade-offs by changing cluster sizes and cluster members using the directory facilitators.  
         [0023]     The autonomous control unit may connect to different numbers of directory facilitators under predefined conditions of the bidding process.  
         [0024]     Thus it is an object of at least one embodiment of the invention to allow change in clusters, including the destruction of clusters and the formation of new clusters during the bidding process as required.  
         [0025]     These particular objects and advantages may apply to only some embodiments falling within the claims and thus do not define the scope of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]      FIG. 1  is a phantom view of a warship showing a simplified set of distribution systems for chilled water, electrical power and compressed air having nodes and branches under the control of autonomous control units;  
         [0027]      FIG. 2  is a schematic representation of these multiple distribution systems showing agents for control of the various nodes and branches of  FIG. 1  communicating among themselves and showing communications across coupled distribution services per the present invention;  
         [0028]      FIG. 3  is a schematic representation of the distribution systems of  FIG. 2  showing a logical clustering of agents according to clusters defined by directory facilitators the latter of which may be changed to change the cluster sizes; and  
         [0029]      FIG. 4  is a more detailed view of a directory facilitator communicating with an agent showing a change of cluster scope according to the results of the bidding process.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0030]     Referring now to  FIG. 1 , a warship  10  may have a variety of separate distribution services, for example, including a chilled water service  12   a , an electrical power service  12   b , and a compressed air service  12   c , each for distributing respectively, chilled water, electrical power and compressed air throughout the warship  10 . The warship  10  is representative of a general distribution system infrastructure such as may be found in other systems such as aircraft and submarines, and in environments such as factories and cities.  
         [0031]     Each of the distribution services  12  may be characterized as a set of nodes  14  joined by branches  16 . For the chilled water service  12   a  and the compressed air service  12   c , the nodes  14  may be motor-pumps, tanks, valves and sensors and the branches  16  pipes. In the case of the electrical power service  12   b , the nodes  14  may be generators, batteries, fuel cells, power loads, power converters, switches and sensors and the branches  16  wires. Other distribution services that distribute utilities such as fuel, compressed air, fresh conditioned air, fire water, elevators, and ballast water may also be found in the warship  10  but are not shown for clarity. Generally but not necessarily, each of the distribution services  12  operates independently, in parallel, and shares no common nodes  14  or branches  16 .  
         [0032]     Referring now to  FIG. 2 , each distribution service  12   a - 12   c  may be controlled by a series of autonomous control units (ACUs)  18 . ACUs  18  suitable for use in the present invention are described in U.S. patents: U.S. Pat. No. 6,091,998 issued Jul. 18, 2000; U.S. Pat. No. 6,272,391 issued Aug. 7, 2001; and U.S. Pat. No. 6,647,300 issued Nov. 11, 2003; and pending U.S. applications: Ser. No. 09/407,474 filed Sep. 28, 1999; Ser. No. 09/621,718, filed Jul. 24, 2000; and Ser. No. 10/242,597 filed Sep. 12, 2002 all assigned to the present assignee and hereby incorporated by reference.  
         [0033]     Each ACU  18  represents a separate logical entity capable that may be associated with each of the nodes  14  and branches  16  to monitor that particular component of the distribution service  12  and to act as its agent in organizing the components to work together in particular distribution tasks.  
         [0034]     Each ACU  18  is logically separate and preferably many ACUs  18  are independent electronic computers so as to provide a distributed computing environment more tolerant of damage and providing sustained operation if several components fail or become disabled. The ACUs  18  communicate with each other preferably by means of a network of a type well known in the art (not shown).  
         [0035]     As described in the above referenced patents and co-pending U.S. patent applications, each ACU  18  is programmed with: generalized knowledge of the capabilities of its associated node  14  or branch  16 , the functional connections between its associated node  14  or branch  16  and at least some other nodes  14  and branches  16 , a bidding protocol, and the ability to interpret and parse a job instruction written in a job description language (JDL).  
         [0036]     Based on a job instruction provided to the ACUs  18  and propagated through the network, for example, to deliver a certain quantity of chilled water to a particular consumer, the ACUs  18  may organize themselves to complete the job based on the current capabilities of their associated nodes  14  and branches  16  and previous commitments of these resources or perhaps likely or expected future capabilities or future operating requirements. In organizing themselves, the ACUs  18  identify portions of the job that they can complete and pass other portions of the job along to other ACUs  18  associated with nodes  14  or branches  16  that may complete the remaining portions of the job. The passage of the job among the ACUs  18  creates bid chains which ultimately are compared to select a winning bid.  
         [0037]     In creating the bid chain, each ACU  18  looks at a subset of other ACUs  18  and  18 ′, within a “cluster” for complementary resources needed to complete the job. Thus, ACUs  18  and  18 ′ evaluating a job for delivery of chilled water communicate with those ACUs  18  and  18 ′ associated with nodes  14  and branches  16  of the chilled water service  12   a . Only ACUs  18  from this cluster will be part of the winning bid. Thus the chilled water service  12   a  defines generally a cluster  22   a , the electrical power service  12   b  defines generally a cluster  22   b  and the compressed air service  12   c  defines generally a cluster  22   c  and typically jobs related to a particular service is passed primarily among the ACUs  18  within the clusters  22  of these services. The use of clusters  22   a - 22   c  greatly simplifies the bidding process by limiting the universe of potential bid participants and bid permutations.  
         [0038]     The topology of a given organization of ACUs  18  is shown by communication paths  20  representing communications between the ACUs  18  required for the execution of that job and representing a subset of the larger scale communication between ACUs  18  over the network during the organizational process.  
         [0039]     As will be understood by those of ordinary skill in the art from this description and the cited applications, a similar organization of ACUs  18  can be effected for the electrical power service  12   b  and the compressed air service  12   c , each controlled by separate job instructions passed among independent ACUs associated with those particular distribution services  12 .  
         [0040]     As a first approximation, a job of distributing chilled water will best be addressed by ACUs  18  associated with nodes  14  and branches  16  (shown in  FIG. 1 ) of the chilled water cluster  22   a  and similarly the job of distributing electrical power and compressed air will best be addressed by ACUs  18  associated with the electrical power cluster  22   b  and compressed air cluster  22   c  respectively.  
         [0041]     Nevertheless, the present inventors have determined that despite this logical partitioning of ACUs  18  into clusters  22   a ,  22   b  and  22   c , improved solutions sets can be obtained in some cases by allowing certain ACUs  18 ″ to communicate with multiple different clusters. Thus one ACU  18 ″ of cluster  22   a  may communicate with a corresponding ACU  18 ″ of electrical power cluster  22   b.    
         [0042]     This communication across clusters  22  may be illustrated by a simple example in which a water distribution problem occurs because of failure of a pump. ACUs  18  looking solely within their cluster  22   a  may attempt to reroute the water flow using a secondary or backup pumps, but in certain cases that may be impossible or may carry with it an extremely high performance penalty. By allowing some of the ACUs  18 ″ of chilled water cluster  22   a  to communicate with ACUs  18 ″ of electrical power cluster  22   b , the ACUs  18  may discover, for example, that the pump failure was caused by a lack of electrical power or a power problem such as a phase imbalance. Cooperation between chilled water clusters  22   a  and electrical power cluster  22   b  through this communication path  20 ″ can allow this knowledge to be incorporated into the optimization of the bidding process of each service (i.e. chilled water and electrical power) while preserving the cluster concept prevents the need for a complete expansion of the solution space such as could create problems of communication bandwidth and solution convergence. The association of nodes from different clusters  22  is called a cluster association.  
         [0043]     In the example of  FIG. 2 , selected ACUs  18 ″ will communicate with other ACUs  18 ″ across boundaries of clusters  22   a ,  22   b  and  22   c  as may be appropriate. For example, typically an ACU  18  associated with a pipe of a chilled water service  12   a  may not communicate with ACU  18  associated with the electrical cluster  22   b , but in the example of the failed pump above, such communication could be useful. In a similar manner, ACUs  18 ″ of the electrical power cluster  22   b  may communicate with the ACUs  18 ″ of the compressed air cluster  22   c  and ACUs  18 ″ of the compressed air cluster  22   c  may communicate with the chilled water cluster  22   a . Generally this intercommunication provides both individual information for optimization and the possible enlisting of resources from the other distribution services  12 , for example, by shutting down an air compressor to save electrical power to provide for chilled water. It also provides for the coordinated reconfiguration of individual services that are coupled, e.g., electrically, mechanically, or functionally.  
         [0044]     Limited connections between the clusters  22   a - 22   c  limits the scalability problems of having too many agents interconnected. It will be understood from review of  FIG. 2  that certain of the ACUs  18 ″ are associated with multiple clusters, for example clusters  22   a  and  22   b.    
         [0045]     Note that the present system allows for multiple overlapping clusters  22 . A pump may be, for example, in a cluster  22  associated with a ballast water distribution service (not shown) and may also be in a cluster  22  associated with a fire water distribution service (not shown). Further, a particular resource (e.g. motor, pump, pipe) may be used in a way not intended during unusual conditions. I understand this is not unique. For example, fuel tanks may be filled with ballast water in emergency conditions. This unusual operating condition may be readily managed by agent clusters.  
         [0046]     Referring now to  FIG. 3 , in an alternative embodiment particular ACUs  18 ′″ may be used to provide for the intercommunication between the ACUs  18  of each of the distribution services  12   a ,  12   b  and  12   c , these ACUs  18 ′″ acting in a supervisory capacity as part of a new cluster  22   d . As a general matter, this supervisory capacity may be extended in hierarchical form to provide for a second higher level of ACUs  18 ′″ forming top level cluster  22   e . In this way, separate job instructions, for example providing for priorities between different distribution services  12   a ,  12   b  and  12   c  or interoperability functions may be integrated into the control process.  
         [0047]     The definition of the clusters  22  may be made in a number of ways, including, for example, programming into each of the ACUs  18  knowledge of its cluster  22 . In this case, the ACUs  18  communicate with only the ACUs  18  of their clusters  22 , thus limiting bands with demands on the system. Alternatively, a directory-type system such as is described in the above referenced U.S. patent applications may be created using a series of directory facilitators  26   a - 26   e , each associated with one of the clusters  22   a - 22   e . An individual ACU, for example ACU  18   a  in cluster  22   a  associated with the chilled water service  12   a , may thus determine its cluster by communicating with a particular pre-assigned directory facilitator  26   a , which lists other ACUs  18  and their capabilities within the particular cluster  22   a , to which ACU  18   a  belongs.  
         [0048]     The directory facilitator  26   a  not only defines a cluster  22  and provides capabilities to improve performance in the searching for other ACUs  18  to meet a particular bid, but also provides a convenient method for programming particular clusters  22  into the system or in dynamically modifying those clusters  22 . Changing the allegiance of ACU  18   a  is readily done by redirecting it to a different directory facilitator  26 , for example the directory facilitator  26  of supervisory agent cluster  22   d , such as may allow it to take advantage of resources of ACUs  18  in supervisory agent cluster  22   d . Conversely, the ACUs  18 ′″ of the supervisory agent cluster  22   d  may communicate with selected ones of the ACUs  18  in the distribution system clusters  22   a - 22   c  by connecting to their directory facilitators  26   a - 26   c  of their clusters  22   a - 22   c.    
         [0049]     The directory facilitators  26  may be implemented within ACUs  18  in a manner ancillary to the other logical functions of the ACUs  18  or in separate hardware attached to the network. Insofar as the directory facilitators  26  are relatively simple tables having the ability to parse requests from the ACUs  18  during bidding, multiple directory facilitators  26  may be contained in hardware for one particular ACU  18  and may be freely created as additional clusters  26  need to be defined.  
         [0050]     Referring now to  FIG. 4 , a particular ACU  18  in attempting to implement a job instruction may thus start by looking at a directory facilitator  26   a  associated with its cluster  22  to see if it can obtain sufficient resources to create a bid chain on the particular job. Thus, for example, an ACU  18  associated with a pump may look at a small local cluster, all or a portion of the chilled water cluster  22   a , to find a necessary pipe and water supply to deliver chilled water to a particular location. In the event that no successful bid is created, or the bid chains do not meet certain threshold criteria, the ACU  18  may expand its cluster by examining also an additional directory facilitator  26   a  to create an expanded cluster  22 , for example, including adjacent distribution services  12 . This is the case for an ACU  18  associated with a pump which cannot produce or find sufficient pumping capacity in its natural cluster  22 , and thus examines ACUs  18  of the electrical power cluster  22   b  to look for solutions which may, for example, include providing additional power to a disabled pump. A nested hierarchy of directory facilitators  26  providing a dynamically changing cluster can thus be created.  
         [0051]     The definition of clusters  22  may change arbitrarily with new clusters  22  created and old clusters  22  destroyed as determined by the progress of the bid, an operational state of the control system, or under the control of supervisory ACUs  18  of supervisory agent cluster  22   d.    
         [0052]     The organization of ACUs  18  into clusters  22  permits various levels of granularity and problem-solving, and flexible trade-offs between solution time, bandwidth and problem solving sophistication. The clusters  22  may be used not simply for control, but also for other ACU functions, such as simulation, reconfiguration, monitoring, modeling, diagnosis or prediction.  
         [0053]     The directory facilitators  26  may provide “blackboard” communication techniques, in which communication between ACUs  18  is accomplished on demand by exchanging information entered on a blackboard without the need for broadcasting or point-to-point communication.  
         [0054]     It will be understood by one of ordinary skill in the art that the clusters  22  can provide diagnostics, re-configuration, control, surveillance, and threat assessment/risk assessment as well as simple control of nodes and branches and that although the examples given are for a ship systems they are applicable equally to commercial, industrial, and vehicle (e.g. aircraft) systems. The ACU and clusters described above are those used in distribution services but the invention does not preclude connections with other relevant systems . and components such as propulsion components that may need to be part of the cluster but are not technically a distribution service.  
         [0055]     It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.