Abstract:
A self-configuring and self-learning network optimizes itself for battery usage, and allows users to simply mount modules implementing new functionality to the vehicle at any location on the vehicle. The use of network zones and wireless gateways between zones reduces network traffic within zones by isolating data not required outside a zone from the other zones.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field 
         [0002]    The present invention relates to motor vehicle control networks. 
         [0003]    2. Description of the Problem 
         [0004]    In a commercial vehicle such as a Class 8 truck, there are innumerable combinations of both original equipment manufacturer (OEM) and aftermarket accessories that can be added to the vehicle to support the various vocations to which the vehicle is applied. Many of the aftermarket accessories require sensors or actuators, and control modules for these devices, along with the associated wiring and connectors. From time to time sensor technologies change and new applications are developed. The implementation of few features may require the availability of a control module that receives analog or digital sensor signals via hard-wired connections. While the vehicle&#39;s electrical control unit (ECU, a type of body computer) can be used if sufficient input ports are available, often an additional controller module needs to be added to the system. The transmission of signals between a sensor and a module is normally achieved by placing a voltage on a signal line, which is read by the receiving module. Sometimes, a special communication protocol is used, such as LIN or CAN, which allows use of a time division multiplexing of control and data signals on a single physical transmission medium, thus limiting the number of signal wires. But even this partial solution still requires wires for the delivery of power to the devices and to ground the devices. And a connection into the transmission medium is still required too. One way or another, the adding of new electrical or electronically controlled features has required adding wiring to the vehicle&#39;s harness. This, in turn, requires additions or changes to routing and clipping, which varies widely from vehicle to vehicle. Therefore, a single sensor addition or change may require several different harnesses and other changes in order to accommodate all of the intended vehicles. Thus, the cost and time required to add even a simple feature is sometimes makes otherwise desirable changes impractical. 
         [0005]    Some of the most common service issues in commercial vehicles are related to wiring or connector failures. Each addition of wiring to the wiring harness to support a device or module increases the possibility of an in service failure. If a sensor or actuator control module is damaged, all of the sensors and actuators connected to the module are rendered useless. A damaged module, or an issue with electrical and electronic connections to the module can force a vehicle out of service. 
         [0006]    A wired network holds limited capability for dynamic changes to a system (addition, subtraction, or movement of sensors and modules), or for enabling a reduction in the required number of modules. A wireless network can improve upon this. However, there still may be compatibility issues with various protocols, along with signal routing issues when system changes occur dynamically. 
         [0007]    A physical communication medium on a vehicle used for time division multiplexed communications will still have a limited capacity for message traffic. As more modules that are added to the system, the more of this limited capacity is used and the greater the possibility of an unacceptable level of data traffic collisions. As available capacity is lost, designers lose the ability to add new features that require such communication. 
         [0008]    To add a new feature to a vehicle, it has usually been necessary to reprogram a central controller, such as an ECU or an electrical system controller (ESC). Any number of different program loads can be requested by customers, making vehicle electronic configuration difficult or complex. 
         [0009]    Naturally, wireless networks require power, as well. Even if power is supplied to sensors by hard wired power and ground, connections, wiring must still be added. This reduces the advantages hoped for when implementing a wireless system, in terms of system complexity and quality. However, signal wires are not required, so some benefit remains. If batteries are used to power the sensors, potential issues arise in terms of battery life and reliability. 
         [0010]    Some prior art references have recognized some of these difficulties. U.S. Pat. No. 6,629,032 taught a wireless vehicle communication system which provided a plurality of electrical control units with wireless transceivers and a dedicated gateway controller. Subsets of electrical control units selected on functional relatedness were organized into networks by joint use of a particular communication code (more precisely a pseudo-random noise code). Communication between networks occurred through the gateway controller. 
       SUMMARY OF THE INVENTION 
       [0011]    It is an object of the invention to reduce system complexity and free the manufacturers and operators of these vehicles from the restraints of a hard-wired sensor/actuator network. 
         [0012]    It is another object of the invention to reduce electrical failures, increase fault tolerance, and add redundancy. 
         [0013]    It is a still further object of the invention to address the issue of network power, via rerouting, and battery conservation, among other means. 
         [0014]    It is yet another object of the invention to allow changes or additions to the system which are “plug-and-play”, so that changes can be made transparently and seamlessly without operator intervention for system reconfiguration. With the ability to provide new features which can simply be “bolted on” to the vehicle, and automatically configured through the network, new or changed features would be less expensive and simpler to implement. 
         [0015]    It is still another object of the invention to greatly increase data transmission capacity to allow for much greater flexibility in design, and to provide infrastructure for unknown future features to be added. It is a further aim to provide increased fault tolerance and redundancy. 
         [0016]    The invention provides a self-configuring and self-learning network that optimizes itself for battery usage, and allows users simply to mount modules and devices implementing new functionality on the vehicle at any location on the vehicle. By simply adding a feature software module to the central controller, the system will configure itself and be ready for use. Optionally, the added feature module can download its operating program or algorithms to the central controller automatically, so no manual update to the controller is necessary. Network protocol accepts any kind of sensor or actuator device that uses radio frequency (RF) communication. Therefore, any RF sensor or actuator device will be added to the network dynamically, without regard to any particular platform or protocol. By implementing multiple networks divided by zones, the system is able to accommodate a greater number of modules and devices and a greater volume of bus traffic. Gateways between zones block the passing of messages in one zone not of interest to modules and controllers in other zones. Zones are preferably spatial rather than logical, and may include a mix of wireless and bus communication traffic, which reduces the need for some wiring and eases the task of making the system dynamically scalable. Additionally, the architecture creates an environment where the presence of faults can be more readily detected and bypassed or even repaired. Similarly, the addition and withdrawal of network objects is dynamically recognized, with the result that the system is effectively dynamically scalable. 
         [0017]    Additional effects, features and advantages will be apparent in the written description that follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
           [0019]      FIG. 1  is a system architecture schematic; 
           [0020]      FIG. 2  is a system network topology superimposed on a vehicle chassis; 
           [0021]      FIG. 3  is a system block diagram for a wireless gateway; and 
           [0022]      FIG. 4  is a high level block diagram of the network of  FIG. 2 . 
           [0023]      FIG. 5  is a state diagram. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    Referring now to the drawings and in particular to  FIG. 1  a network architecture  10  is shown which illustrates various possible components, and a possible combination of those components, in a preferred embodiment of the invention. The highest ranking components in the network hierarchy are network objects  12 ,  14 . Network objects  12 ,  14  may be implemented as SAE J1939 compliant controller area networks (CAN), or they be implemented using any one of plurality of other supported network protocols. For example, network object  12  may include a CAN compliant cable  30  as a hardwire communication link while network object  14  includes a local area network (LAN) bus as its hardwire communication link. Network objects  12 ,  14  communicate with one another when required through bridge gateways  16 ,  18 . A bridge gateway  16 ,  18  may provide either a wireless or hardwire connection between the network objects  14 ,  16 . A bridge gateway provides translation of messages if the network objects operate under different communication protocols and the messages require transfer between network objects. Bridge gateways connected to CAN systems are programmed to determine classes of messages which require such transfer. A network object may be entirely wireless or include a hardwire communication link such as a bus or twisted pair cable. 
         [0025]    Network objects  12 ,  14  may contain any number of device objects (DO) and modules. A device object is categorized as “smart” or “dumb” and may be a sensor, display, actuator, or other device. A “smart” device may include sufficient local data processing capability to recognize the communication protocol of its local network zone and format messages for the local network and will at least be capable of independent operation. A “dumb” device may be a slave device of another controller, or a module, of its local network object. A variety of device objects are illustrated including an aware device object  36 , which includes an antenna  38  for wireless communication with a gateway and a physical connection into a communication link  40  for network object  14 . Device object  36  is a telematics module, which provides wireless connection to remote operational centers for downloads of data and programs or uplinking of operational data. An antenna  38  is provided. 
         [0026]    Another device object, a smart sensor  28 , provides only a physical link to CAN cable  30  of network object  12 . A second smart sensor  32  includes an antenna  34  and is linked into a network object by a wireless link to a local bridge gateway  18 . Sensor transmit data. Gauges may be provided, such as device object  42  which take data off a network object for display. Device object  42  includes an antenna  44  for wireless linkage to a network object. All of these devices are intended for installation on a vehicle. 
         [0027]    Tool objects (TO) are devices not intended for permanent installation on a vehicle and which can tap into a network object  12 ,  14 , preferably wirelessly (as illustrated by a laptop computer  24  with its associated antenna  26 ) or by a diagnostic port if necessary. Tool objects temporarily join a local zone and are used by network administrators and technical personnel to monitor bus traffic, configure device objects if required and carry out other diagnostic activities. 
         [0028]    Bridge gateways  16 , 18  allow any number of network objects to be interlinked. In the embodiment shown in  FIG. 2 , a commercial vehicle deploying three network objects is depicted. A base vehicle that provides only basic motive transportation would typically include only one network object, which would connect vocational controllers such as a brake controller, transmission controller, engine controller and body computer or electrical system controller might be present in addition to the bridge gateway controller. Due to the operational criticality of the bus connecting such elements it may be considered problematic to load that bus with additional controllers, sensors and gauges which generate or attract bus data traffic. As a truck is equipped with additional features it could be equipped with the base network object and a secondary network object linked to the first by a bridge gateway. The additional features would be accommodated by the secondary network object. Finally, a trailer could be equipped with a local network which can become either the second or third network object in a compound vehicle when the trailer is attached to the base vehicle, or to the enhanced base vehicle if equipped with a bridge gateway. Detachment of the trailer would result in reversion of the base vehicle to its base network topology. Thus the system is dynamically scalable and may include a number of network objects greater or fewer than three, all achieved by the incorporation of bridge gateways to add network objects. 
         [0029]      FIG. 2  illustrates a control system for a commercial vehicle based on an extended truck chassis  50 , different areas of which are covered by distinct network objects  52 ,  54 ,  56 , locationally corresponding to spatially distinct zones  1 ,  2  and  3 , respectively. The zones are illustrated two dimensionally as non-overlapping sectors laid out from front to back along the truck chassis  50 . In terms of physical connections it is expected that modules and sensors having a direct physical connection to the electrical or optical cabling of the vehicle for signaling will be located in the zone corresponding to the cabling to which they are attached. Exceptions to such a rule due to difficulties in attaching a particular node to the data transmission means are possible. The cabling, as distinguished from wireless links, is considered the physical layer of the network objects. To illustrate the flexibility of the system topology, some operationally essential control units have been distributed among the network objects  54 ,  56  outside the base network object  52 . Functionally related devices are usually distributed among the local zones rather than being attached to a network organized by function of the devices. For example, six wireless tire pressure management sensors (TPMS)  58  are located on the chassis  50 . Two forward TPMS devices  58  are associated with zone  1  and four aft installed TPMS devices  58  are associated with zone  3 . The forward TPMS devices  58  are linked into network object  52  by wireless links with bridge gateway (WG)  60 . The four aft installed TPMS devices  58  are linked into network object  56  by wireless links implemented by an aft bridge gateway (WG)  62 . Modules, such as vehicle sensor module  80  or remote power module  82  may be used as an interface between the network object and sensor or actuator device objects. 
         [0030]    Moving from front to back of chassis  50 , a forward network object  52  is shown including representative modules such as vocational controllers, including an electrical system controller  64  and an engine controller  66 . Representative of other elements of a vehicle with communication requirements are actuator devices  72  for door systems, such as locks and power windows (door pods) and a non-specified controller  74 . A remote power module  68 , used generally to actuate systems and a vehicle sensor module  70 , used for incorporating additional sensors (e.g. ambient temperature gauge, anti-lock brake sensors, etc.) are also attached to and incorporated in the forward network object  52 . A wireless display gauge  76  is physically located in the forward part of the vehicle, and will typically be included in network object  52  through a wireless link to bridge gateway  60 , though it may be incorporated into middle network object  54 . 
         [0031]    A middle network object  54 , which is physically located in zone  2  provides a physical data link between bridge gateways  60  and  62 . Three device objects are illustrated as part of network object  54 , a transmission control unit (TCU)  78 , a remote power module  82  and a vehicle sensor module  80 , all of which are physically connected to the network object physical communication link. Further aft on chassis  50  is an aft network object  56  which includes yet another remote power module  86  and vehicle sensor module  84 . A wireless sensor  88  is located in zone  3  and communicates with the network object  56  via a wireless link to bridge gateway  62 , as do four tire pressure management sensors  58 . 
         [0032]      FIG. 3  is a block diagram of a typical bridge gateway  100 . The particulars of the diagram are not particularly significant except to say that a bridge gateway must provide the ability to handle communications over networks operating under a variety of communication protocols and provide for wireless communication. To that end appropriate communication blocks  122 ,  124 ,  126 ,  128 ,  130 ,  132  and  134  for various protocols are provided as well as a universal asynchronous port  118  for handling communications traffic received over a physical layer or by wireless means. The bridge gateway  100  incorporates a power supply  106  for stepping down vehicle voltage, and sufficient memory  104  to provide translation tables and processing capability to determine which messages need to be passed and the ability to translate the message to a different protocol if required and the usually essential CAN controller  102 . 
         [0033]    A main processing block includes basic input/output sections  108 ,  110  (relating to digital and analog communications) and the sections  112 ,  114 ,  116  and  120  implementing the processor. The arrangement is by and large conventional network gateway technology. 
         [0034]    Referring to  FIG. 4 , a hypothetical topology for a system incorporating three network objects  152 ,  154 ,  156  is depicted. The network objects are not distinguished, though network object  154  may be taken as corresponding to a middle zone network object for vehicle, e.g. network object  54  of  FIG. 2 . Two bridge gateways  160 ,  162  provide for exchange of data between network objects. Bridge gateway  160  is physically connected to the physical communication media (layers) for network objects  152  and  154 . Bridge gateway  162  is physically connected to the physical communication media (layers) for network objects  154  and  156 . It is assumed that network objects  152  and  156  are located is physically displaced zones, however, bridge gateways  160  and  162  can establish a wireless link WL allowing traffic from network object  156  which is required by a module object  170  or device object  172  on network object  152  to bypass network object  154 , and vice versa. The wireless link WL may be invoked upon failure of network object  154 . 
         [0035]    Network objects  152 ,  154  and  156  usually comprise module objects  170  and device objects  172  and may include tool objects  174  from time to time. Device objects  172  may include a module object  170  as an interface to the network object. Device objects  172 , as already specified, may be dumb devices or smart devices. Generally dumb devices  172  require a vehicle sensor module (VSM) to provide an interface to the network object. 
         [0036]      FIG. 5  illustrates a state diagram for a bridge gateway. Upon power up (state  180 ) a state change to operation mode (state  182 ) is forced. From the operation (state  182 ) mode four possible state transitions are possible, including a default power down mode (state  194 ) which occurs upon a loss of power or when the system is turned off from any state. In operation mode a bridge gateway monitors message traffic on each of the network objects it is connected to (typically two). Upon receipt of a download command a state transition occurs to download mode (state  184 ). Upon completion of a download a state transition automatically occurs back to the previous state (either operation mode (state  182 ) or bridge mode (state  186 )) or to a sleep mode (state  188 ). Upon receipt of a message requiring translation to another network object a state transition to bridge mode (state  186 ) occurs. In bridge mode (state  186 ) identification of an operation command results in a change of state to operation mode (state  182 ) and identification of a download command results in a state change to the download mode (state  184 ). 
         [0037]    A lack of activity, or a specific sleep command, results in a change of state to sleep mode (state  188 ) to save power. Sleep mode is interrupted with network activity or a change in key state (e.g. accessory to start). Periodic events triggered by a system clock  190  may require temporary changes in state from sleep mode (state  188 ) to a report mode (state  192 ). 
         [0038]    While the invention is shown in only one of its forms, it is not thus limited but is susceptible to various changes and modifications without departing from the spirit and scope of the invention.