Reconfigurable virtual backplane systems and methods

Reconfigurable virtual backplane systems and methods are provided. One virtual backplane system includes a bus, and first and second line cards coupled to the bus. Each line card includes a processor including a memory storing an array of configuration tables. Each configuration table stores a listing of processes to be transmitted to or received from the communication bus, wherein a first configuration table is selected from the first line card upon the occurrence of a first event and a second configuration table is selected from the second line card upon the occurrence of a second event. One method includes connecting first and second buses in first and second systems, respectively, to form a bus for a new system. The method further includes detecting the connection of the first and second buses, and reconfiguring the first and second systems to operate as the new system in response to detecting the connection.

FIELD OF THE INVENTION

The present invention generally relates to the field of computer platform control systems used in, for example, spacecraft, aircraft, habitat, and robotic systems, and more particularly relates to reconfigurable virtual backplane systems and methods.

BACKGROUND OF THE INVENTION

Aircraft and spacecraft control systems are responsible for controlling various systems in an aircraft, such as “fly by wire” guidance and navigation systems, aircraft lighting systems, aircraft environmental control systems, aircraft flight control systems, and aircraft flight management systems. Over time, different types of vehicle control systems have been proposed to provide control functionality while minimizing size, weight, and cost.

One type of control system is a federated system, which provides a dedicated box, typically referred to as a line replaceable unit (LRU), for each control function. For example, in a federated system, a separate LRU is provided for the autopilot system, the navigational system, and the like. Drawbacks to federated systems may include excessive weight, large size, and high cost.

To overcome some of these drawbacks, integrated LRU systems that combine several systems into a single LRU have been used. By consolidating several systems into a single LRU, savings in size, weight and cost can be achieved. However, when several systems are integrated into a single LRU, failure of a single system requires replacement of the entire LRU.

A more recent approach is the integrated modular avionic (IMA) control system. In an IMA system, cabinets containing one or more circuit cards replace the LRUs. A single circuit card or collection of circuit cards contains the electronics necessary to provide a function such as navigation or flight control. If a failure occurs, individual circuit cards are replaceable. In this approach, because of the integration at the cabinet level, it is difficult to create a system that implements functions using multiple cabinets.

To overcome some of these drawbacks, yet another approach utilizing a virtual backplane has been suggested. In a virtual backplane system, the actual location of an element that provides some function is unimportant since data needed by each element is placed on to a common communication bus at a regular predetermined rate. Previously, at the cabinet level, all elements could share data since they were all coupled to the same backplane. However, data exchange between cabinets was limited to typically some element needing to request data in order to receive the data. In the virtual backplane system, each of the elements in each of the cabinets sends and receives information according to a predetermined sequence stored in memory. In this way, an element may be located in any cabinet and behave as if interacting elements were in the same cabinet.

The most recent approach to the virtual backplane system utilizes a fixed schedule of activity on the bus. In this case, the activity that occurs on the backplane is pre-determined prior to system use and does not change during the operation of the computer platform system. The drawback of this system approach is that a single circuit card or collection of circuit cards or a new function within existing cards cannot be added to the architecture while the system is in operation.

BRIEF SUMMARY OF THE INVENTION

Various embodiments provide reconfigurable virtual backplane systems. One reconfigurable virtual backplane system comprises a communication bus and first and second line cards coupled to the communication bus. The first line card includes a first processor comprising a first system memory, the first system memory storing a first array of configuration tables. Each configuration table in the first array stores a listing of processes to be transmitted to or received from the communication bus, wherein a first configuration table is selected from the first array of configuration tables upon the occurrence of a first predefined event. The second line card includes a second processor comprising a second system memory, the second system memory storing a second array of configuration tables. Each configuration table in the second array stores a listing of processes to be transmitted to or received from the communication bus, wherein a second configuration table is selected from the second array of configuration tables upon the occurrence of a second predefined event.

Various embodiments also provide line cards configured to be coupled to a communication bus in a modular unit. One line card comprises a processor including a system memory, the system memory storing a plurality of configuration tables. Each configuration table comprises a listing of processes to be transmitted to or received from the communication bus, wherein a first configuration table is selected from the plurality of configuration tables upon an occurrence of a predefined event.

Methods for forming a new system comprised of a first system including a first communication bus and a second system including a second communication bus are also provided. One method comprises the steps of connecting the first communication bus and the second communication bus to form a third communication bus for the new system and detecting the connection of the first communication bus and the second communication bus. The method further comprises the step of reconfiguring the first system and the second system to operate as the new system in response to detecting the connection.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1illustrates one embodiment of a virtual backplane system100used in an aircraft50; however, this embodiment could also be used in a spacecraft, a habitat, a robot, or like integrated control system. At least in the illustrated embodiment, aircraft50includes a computer network104comprising a plurality of modular units (MU)102coupled to one another via a system bus106.

Each MU102is configured to support various processing and input/output (I/O) tasks. For example, a first MU102can be used to provide a collision avoidance system for aircraft50, a second MU102can be used to provide a flight management system for aircraft50, a third MU102can be used to provide a cockpit display system for aircraft50, a fourth MU102can be used to provide an autopilot system for aircraft50, and so on.

System bus106may be any system and/or device capable of allowing MUs102to communicate with one another. Furthermore, system bus106may be a wired and/or wireless bus. Wired buses may include both electrical buses and non-electrical buses that support the transfer of data, such as wire lines, optical fibers, and the like. Additionally, system bus, while shown inFIG. 1as a single bus, system bus106may also include multiple redundant buses.

The communication occurring on system bus106is predetermined, but can be reconfigured during real-time operation by events within a MU102or by the addition of one or more MUs102on system bus106or the subtraction of one or more MUs102from system bus106. In one embodiment, system bus106behaves as a reconfigurable virtual backplane connecting the individual MUs102. In this embodiment, each MU102is capable of communicating with one another as if they were a single MU102. That is, instead of one MU102sending a request for data over system bus106to another MU102, data is placed on system bus106and retrieved from system bus106in a predetermined, deterministic manner, using, in one embodiment, configuration tables. In addition, the tasks performed by the MUs102can also be reconfigured dynamically during real-time operation based on the occurrence of an event, as will be discussed in greater detail below.

FIG. 2is a block diagram of an exemplary embodiment of a MU102. MU102includes one or more line cards202coupled to one another via an internal backplane204. MU102also includes a Network Interface Card (NIC)206coupled to the internal backplane204and to system bus106.

In one embodiment, each line card202provides processing and I/O functions for MU102, which may be loaded with software configured to perform particular tasks. For example, in an avionics embodiment, line cards202may be programmed to perform collision and/or terrain avoidance functions.

Backplane bus204provides a common communication connection between each line card202and NIC206in MU102. Typically, line card202connects to backplane bus204via a physical insertion of the line card202into a slot (not shown) of the backplane bus204. Alternatively, different ways of connecting line cards202to backplane bus204can be used including, for example, wired and/or wireless connections.

NIC206communicates with the reconfigurable virtual backplane system bus106by placing data on system bus106and retrieving data from system bus106. As discussed above, NIC206also receives data from and sends data to line cards202. In one exemplary embodiment, NIC206sends and receives data from data bus106at a predetermined schedule, which is described in greater detail below.

FIG. 3is a block diagram of one embodiment of line card202. Line card202, at least in the illustrated embodiment, comprises a processor302coupled to a system memory304, and optionally an input/output interface303. As discussed above, line cards202can execute software programs to provide different functionalities.

Processor302may be any high integrity processor known in the art or developed in the future. In one embodiment processor302is configured to execute software assigned to run on line card202. Although processor302is illustrated inFIG. 3as a single processor, processor302can be deployed in any needed redundant configuration such as, but not limited to, a lock step or triple modular redundant processor configuration.

I/O interface303provides an input/output interface to backplane bus204. Processor302is operable to indicate what data the I/O interface303should place on backplane bus204, when to place the data on to backplane bus204, and the rate at which to place the data on backplane bus204. In addition, processor302is operable to instruct I/O interface303when to retrieve data from backplane bus204and what data to retrieve.

System memory304is configured to store data and program files that are executed using processor302. System memory304is preferably a readable/writable memory that can be updated when needed. In one embodiment, multiple applications can be stored in system memory304. The applications selected to be executed may be selected based on the occurrence of an event, as will be discussed in detail below.

System memory304also comprises one or more table memories402, as illustrated inFIG. 4. Each table memory402comprises a plurality of configuration tables406. Configuration tables406, in one embodiment, include information as to what programs and sequence of events that should be executed by processor302and what data is to be presented to and from virtual backplane system100. In addition, configuration tables406may contain information as to what data needs to be placed or retrieved from backplane bus204, when to place or retrieve the data and the rate at which the data is to be placed on or retrieved from backplane bus204. The applications running on processor302use configuration tables406to determine the data retrieval and/or placement information.

System memory304associates each of configuration table406with the occurrence of one or more specific events. For example, a given line card202may be associated with one task until a certain amount of time has passed. When the time elapses or a predetermined event occurs, system memory304may be used to determine a new configuration table (e.g., configuration table406a) to use. Configuration table406acould then change what processor302is doing, such as by starting a new application and changing the information flow on virtual backplane system100. Configuration table406amay also change the data retrieved from and sent to the backplane bus204.

In this exemplary embodiment, the use of configuration tables406allows data to be provided or sent in a predetermined, deterministic manner. The ability to change configuration tables406based on the occurrence of an event gives line card202the ability to be a reconfigurable line card.

In one exemplary embodiment, an event that can cause a change in the configuration tables may include a change in the number of line cards202operating at any given time. The change in the number of operating line cards202may include the failure or loss of a line card202. If a line card202malfunctions, a new configuration table406can be used to instruct another line card202to take over for the failed line card202. Additionally, the change in the number of line cards202may include the addition of a line card202to a particular MU102. The addition of a line card202may result in a new configuration table406that has the new line card202takeover some process functions from one or more other line cards202. A change in the number of operating line cards202also includes the situation where there is the same number of failed line cards202as there are new line cards202.

In another embodiment, an event that can cause a change in configuration tables406is a change in software functionality. A change in software functionality may include the loss of software functionality or the addition of a software functionality.

Various embodiments contemplate that additional configuration tables may be provided as needed. For example, if an event occurs that does not have a configuration table406, an appropriate new configuration table406can be generated. In one embodiment, the new configuration table406can be generated by virtual backplane system100. In an alternate embodiment, the new configuration table406can be generated by a third party and provided to virtual backplane system100. For example, if virtual backplane system100is deployed in a spacecraft, ground control could provide the new configuration table406to virtual backplane system100.

In the embodiments shown inFIGS. 2-4, backplane bus204couples each line card202within a MU102to one another. In another exemplary embodiment, a plurality of MUs102may be coupled to one another via a virtual back plane connection.

FIG. 5is a block diagram illustrating a plurality of MUs102coupled to one another to form a new system500. For example, system500may be formed from the connection of a first spacecraft550(e.g., a lunar module) and a second spacecraft (e.g., a lunar orbiter)570. Specifically, system500is formed when a MU5500in spacecraft550and a MU5700in spacecraft570become connected by a common system bus506, which can act as a configurable, virtual backplane bus.

In the embodiment illustrated inFIG. 5, MUs5500and5700each comprise one or more line cards5502and5702, respectively. Lines cards5502and5702are each coupled to one another via an internal backplane5505or5705, respectively. MUs5500and5700each also comprise a bridge connector5508and5708, respectively, coupled to their respective internal backplanes5505and5705.

Bridge connectors5508and5708each serve as a network interface card connecting MUs5502and5702to system bus506. Bridge connectors5508and5708, in one embodiment, each include a bridge configuration memory5512and5712, respectively, that include a table memory comprising a plurality of configuration tables within a system memory. As discussed above, each configuration table provides the application running on the bridge connector with information regarding what data to place on or receive from system bus506, when to place or receive the data, and at what rate the data is placed on or received from system bus506.

In one exemplary embodiment, line cards5202and5702each include a system memory similar to system memory304discussed above with reference toFIG. 3. In this embodiment, backplane buses5505,5705and system bus506act as configurable, virtual backplanes. In this manner, the occurrence of an event could change the way any of line cards5202and/or5702, and/or bridge connectors5508and/or5708operate.

In another exemplary embodiment, line cards5502and5702are commercially available line cards and backplane buses5505and5705serve to couple their respective line cards in a conventional fashion. For example, backplane buses5505and5705may each be a peripheral component interconnect (PCI) bus. In this embodiment, bridge connectors5508and5708allow MUs5500and5700to be connected using a reconfigurable virtual backplane.

The exemplary embodiments discussed previously have dealt with either a reconfigurable virtual back plane coupling individual line cards in a MU or MUs coupled by a virtual backplane (whether or not the line cards within the MUs are coupled by a virtual backplane). Another exemplary embodiment of the present invention is illustrated inFIG. 6, which shows two different systems, a first system6500and a second system6700, from different networks forming a new system600.

At least in the illustrated embodiment, system600couples MUs6500and6700to each other by a virtual backplane6505within MU6500and a virtual backplane6705within MU6700. Systems6500and6700, when separated, can each perform different functions. For example, system6500can be a space vehicle that at launch includes the crew, while the second system6700can be a lunar landing vehicle that is launched separate from system6500. At some point in time, the space vehicle and the lunar landing vehicle will dock, which will allow the crew access to the lunar landing vehicle. When system6500and system6700connect to form system600, the virtual backplanes6505and6705are combined to form a combined virtual backplane608. In one embodiment, the virtual backplanes6505and6705are physically coupled upon the docking of systems6500and6700. Alternatively, the virtual backplanes6505and6705can be coupled by a wireless link that does not require exact physical coupling of the backplanes6505and6705.

The connection of systems6500and6700is an occurrence that, when detected, can trigger a reconfiguration of one or more subsystems on systems6500and/or6700. For example, detection of the connection of systems6500and6700can trigger changes to current configurations, such as activating the air conditioning and/or other systems in the lunar module, while altering the flight computer of system6500to compensate for the additional mass of the combined systems. WhileFIG. 6illustrates the connection of systems6500and6700, detection of the disconnection of systems6500and6700can also initiate configuration changes according to a system memory and associated configuration memories included in line cards6202and6702stored in systems6500and6700, respectively, which are similar to line cards202discussed above with reference toFIG. 2. For example, when systems6500and6700disconnect, the air conditioning and/or other systems in the lunar module may return to their operational states prior to connection of systems6500and6700. Likewise, the flight computer of system6500will reconfigure to no longer compensate for the additional mass. In other words, the flight computer will return to its operational state prior to connection of systems6500and6700.