CA2347126C - Configuration programming of input/output connections for network modules in a multiplexed vehicle communication system - Google Patents

Abstract

A control system (10) for a vehicle (13) provides for the control of electrically differentiated loads utilizing a local con- troller, the functionality of which depends upon a programmed central control unit. A first serial data link (18) connects a plural- ity of autonomous local controllers of fixed funtionality to the central control unit. A second serial data link (42) links at least a first dependent controller to electrical sys- tem controller. The electrical system con- troller provides for controlling multiplexing of signals on the first and second serial data links (18) and (42). Memory (60) provides both protected and nonprotected sections, with the protected sections providing stor- age for configuration data structures residing in memory and the data structures providing functional definitions for the first dependent controller. A core program resides in mem- ory (60) for use with the data structures, and a central processor executes the core pro- gram using the data structures for generat- ing control signals for transmission to the dependent controllers. The first dependent controller is responsive to the control sig- nals for assuming specialized control states.

Description

CONFIGURATION PROGRAMMING OF INPUTIOUTPUT CONNECTIONS
FOR NETWORK MODULES IN A MULTIPLEXED VEHICLE COMMUNICATION SYSTEM
BACKGROUND OF THE INVENTION
1. Field of the Invention The present invention relates to multiplexing communication networks on vehicles and more particularly relates to providing a network having a central control module and one or more remote generic modules to provide control of non-standard vehicle vocations as well as specialized controllers for conventional vehicle vocations.

2. Description of the Prior Art At a simple level, communication between two agents may be kept physically separated from communications occurring among other agents. Where two or more signals do not use the same physical space, there is no need to separate the signals in time or in camerwave frequency. Such a communications regime is sometimes termed physical division mu~ipfexing although the term multiplexing is usually reserved to techniques for applying multiple signals to a single medium or physical space. So called physical division Z
muttipiexingdescribes how motorvehicles have been traditionatlywired. The use of separate dedicated wires to connect each switch and lamp is a type of physical division multiplexing.
Obviously, physical division multiplexing, while simple in concept, results in the use of many wires (the classical motor vehicle electrical harness), which are difficult to install during manufacturing and problematic to maintain in the field.
Arrangements allowing a numberof agents to communicate over a common physical layer or medium, offer much greater physical simplicity. Intelligible communication between two or more devices among a greater plurality of devices, all over a common medium, depends upon the communicating devices being able to distinguish, and understand, messages directed to them from other messages which they receive, but which are not intended for them. The process of distinguishing messages depends upon the transmitter of the message applying some attribute to the message which identifies it to the intended recipient. In human conversation, most people readily distinguish speech directed to them from interfering crosstalk in a crowd by the distinctive aspects of the voice of the person addressing them. Where the members of the group are electrical components, the problem still involves identification of a distinguishing attribute of the signal.
Appropriate attributes for signals take a number of forms.
A line communicating a signal from a remote switch to a lamp to turn on or off (by having a second switch, local to the lamp, change states to control connection of the lamp between a power bus and ground) cycles only rarely. In a typical trip such a change in state occurs only once or twice, if at all. Where such a , line is not intended to provide power to the lamp, and simply indicates changes in state for the local switch controlling the lamp, the line will have the capacity to handle far more data than the occasional indications to turn a lamp on and off. The objective of maintaining simplicity in manufacturing and maintenance are preferably met by allowing communication among a number of components to occur in a single medium, or at least as few communication lines as possible. The line used to connect switch and lamp could interconnect a number of components, carrying messages between any grouping of elements connected to the line when not required to cant' an instruction to a lamp to turn on. One way of achieving this objective is a communications regime which divides time into slots during which particularcombinaiions of components have use of a signaling line. Such methods are well known in the art and are examples of time division multiplexing (TOM), in motor vehiGes, time division and related multiplexing techniques offer substantial simplification in physical layer required to support the control of vehicle vocations.
Rigid time division multiplexed communications appear to interleave data signals into a single serial signal over a single physical medium. Multiplexed communication systems also provide the reverse function (demultiplexing) of dividing the single signal into multiple, nonsynchronous digital signals. Where demands on the capacity of the data transmission medium are not especially heavy, any unit may be allowed to claim the medium provided collision detection is provided for and other indicia, such as address headers, indicate the signal's destination.
As applied to motor vehicles, multiplexed communications over serial data paths are an effective technique for reducing the number of dedicated communication paths between the numerous switches, sensors, devices and gauges installed on the vehicles. With each increase in the number and variety of accessories and functions installed on each vehicle, the benefits of using a single, multiplexed communication serial link for passing instructions to and receiving information from vehicle devices as diverse as running lights and rear axle temperature sensors becomes greater. Multiplexing the signals to and from local controllers and switches for vehicle systems promises greater physical simplicity through displacing much of the vehicle wiring harness, reducing manufacturing costs, facilitating vehicle electrical load management, and enhancing system reliability.
The specific manner of implementing multiplexed communications is outside the scope of the present invention, which applies a defined protocol, the SAE J1939 protocol. The development by the Society of Automotive Engineers of the J1939 series of standards for multiplexed communications testifies to the progress in the application of multiplexed communications to vehicles, Standards have been or are being developed relating the communication path, transmission collision detection, diagnostic ports and data protocols, among other topics. The J1939 protocol provides an open protocol and definition of the performance requirements of the medium of the physical layer, but also allows for developmentof proprietary protocols. The SAE J1939 protocol is a specialized application of a controlled area network (CAN) and may be readily implemented utilizing commercial integrated circuits such as the C167 Integrated Circuit from Siemens of Germany.
A serial communications system utilizing a multiplexing regime can link several remote digital controllers positioned around a vehicle with an electrical system controller (ESC) for two way communication.
Remote digital controllers are addressable, allowing them to respond to signals intended for them initialize particular functions. They may also include programming that allows the device to react to local conditions as well as condition indicating signals provided the controller. The ESC may pass requests and instructions received for operations of certain devices, addressed to the correct remote controller, in a fashion to condition the timing and duration of the responses to requests to better manage overall vehicle electrical load, United States Patent 4,809,177 to Windle, et al., which is assigned to the assignee of this patent, relates to a multiplexed communications system in which a central controller organizes signals to various vocational controllers distributed about a vehicle. The distributed controllers included internal data processing capability and programming. Among the controllers were engine, cab and chassis controllers. The environment of Windle et al. is a limited multiplexing environment, where much operational responsibility is distributed to the local, specialized controllers.
Windle et al. teach a controllerconstructed according to a single physical design suitable for use both as a chassis controller and a cab controller. The chassis controller handles the engine brakes, the ignition, the air conditioning compressor and some external lights while the cab controller handled other external lights, the air conditioning compressor, the windshield wiper motor, among other functions. The dual purpose controller is a microprocessor based system running stored programs in local memory. The controller is adapted to handle one or the other of the differing sets of functions by being programmed for those functions and by applying different inputs to the device. Reprogramming involved overwriting non-volatile memory or replacing programmable read only memory units.
Windle et al. recognized that if a controller could be constructed in accordance with a single physical design for different vocations, benefits would be gained in terms of reduced inventory and manufacturing costs, and anticipated improvements in reliability. Notwithstandingthis recognition, the teaching of the Windle patent falls short of teaching a generalized physical layer in which numerous specialized functions are implemented by programming. Windle et al. did not attempt to extend the idea of single design controller outside of an environment where the requirements on the controller could be fully anticipated nor did they attempt to remove specialized programming from the distributed controllers.
Numerous advantages would flow from enabling a manufacturer to provide a chassis with a generalized electrical control layer on which programming could add extensive functionality. For example, builders of luxury coaches, fire trucks and ambulances, all place highly specialized requirements on a vehicle's electrical system which may, or may not, be known to the chassis manufacturer.
In some cases these requirements may even be unique to a particular vehicle. For example, a coach builder may wish to install a highly customized, zone activated air refrigeration system on a vehicle.
Such specialized systems or vehicle vocations have required complex, customized wiring systems to support. Were a coach builder able to adapt a serial communication system to the functionality requirements of the various bodies, and further able to specify accessory functionalitywithout the need to hardwire that functionality into the vehicle, substantial gains in physical simplicity and reliability could be achieved.
Substantial economies of scale could be gained from using a standardized component for several vocations on commercial vehicles. The ability to support such a device would also simplify assembly and allow for smaller parts inventories, as partia8y achieved by Windle et al.
Such a generic control regime would allow greater differentiafion in vehicles to be economically obtainable.
Windle et al. contemplated the use of fully reprogramable local controllers, which were adaptable to a defined sets of tasks by reprogramming. More recently, suppliers of major power train components have included a dedicated controller suitable for managing the component and for communicating with a vehicle electrical system controller using the open protocol of the J 1939 standard.
These suppliers allow a limited type of configuration programming of the controllers for changing the values of certain vehicle operating parameters. Configuration data has been used to change values of certain controlled parameters, such as engine horsepowerltorque output curves, fuel rates and cruise control performance; however, the functional defini~on of the input and output interfiaces of controllers have not been changed and the configuration programming continues to reside in the local controller.
SUMMARY OF THE INVENTION
Accordingly, the invention seeks to provide a vehicle communications and control system supporting uniform physical layers across groups of vehicles of increasingly differentiated vocational requirements.
~o~~ ~p~t of the invention seeks to minimize the number and variety of local controllers required in the physical layer to implement vehicle vocations.
It is a still further aspect of the invention to provide a physical layer for a communications and control system scalable through the use of scalable, functionally generic, local controllers, substantially relieving the communications and control system of input and output resource limitations.

Sa The invention in a broad aspect provides a control system for a vehicle comprising a non-generalized physical layer including a system controller having memory for the storage of programs and data, a plurality of specialized local controllers and a data bus connecting the system controller with the specialized local controllers for the two way communication of information, and a generalized physical layer. The generalized physical layer includes a second data bus connected to the system controller, and at least a first generic local controller having a plurality of standard ports for the connection of controlled devices, the first generic controller being connected to the second data bus to receive data from and transmit data to the system controller, the first generic controller and one or more of the standard ports assuming a functional state in response to instruction data received over the second data bus from the system controller. The system further includes configuration data stored in the memory specifying functionality for at least the first generic local controller and for at least on standard port of the generic local controller, and a core operating program is stored in the memory executable by the system controller on the configuration data for the generic local controller in the generalized physical layer to construct instruction data for implementing a functionality on the generic local controller. Means are provided for transmitting the instructions as data to the generic local controller over the second data bus.
More particularly, according to the inventon there is provided a vehicle having a plurality of electrical loads, differentiated from one another in terms of required voltage, current drawn, load duration and variability of energization levels. The vehicle conventionally includes a plurality of drive train components, such as engines, transmissions and anti-lock brake systems to which electronic control is applied. Each major drive train component has its own autonomous controller, which executes a local program, but which is responsive to requests received by the controller from a control network. Eaeh autonomous controller includes means for receiving requests relating to a drive train component, and means for monitoring drive train component status in order to provide status indications for the component over the network including a first serial data bus to an electrical system controller.

s The invention further includes at least one dependent controller for accessory components. The dependent controller includes a plurality of ports available for functional definition. The dependent controller includes a processor subject to remote control to specify all functions of the. dependent controller. A second serial data bus connects the dependent controller and the electrical system controller.
The electrical system controller includes memory for storing a core program, definition data for the dependent controller and status indications received from both autonomous and dependent controllers. The core program and definition data are preferably stored in nonvolatile memory, but subject to being rewritten if required. The electrical system controlleris based on a central processor~nnected by a bus to the memory for accessing and executing the core program on the definition data and on the status indications. Specific inputs to the dependent controllers are generated both to generate functional definition instructions for the dependent controllers and specific actions to take. The electrical system controllerfurther includes serial bus controllers providing for multiplexing of functional definition instructions on the second serial data bus.
Additional effects, features and advantages will be apparent in the written description that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
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:
Fig.1 is a perspective view of a vehicle electrical system;
Fig. 2 is a high level bloc~C diagram of the control network for a vehicle;
Fig. 3 is a diagrammaticdepiction of the disposition of data interfaces for the central electrical system controller of the invention;

Fig. 4 is a detailed block diagram of the control network of the present invention; and Fig. 5 is a schematic illustration of disposition of the control network of the present invention on a truck.
DETAILED DESCRIPTION OF THE INVENTION
Fig.1 is a perspective view of a vehicle electrical system 10 installed on a vehicle 13. Vehicle control system 10 comprises an electrical system controller (ESC) 30, which is the primary component of a vehicle electronic control system. ESC 30 manages a number of vocational controllers disposed on vehicle 13 and executes a load management program which oversees the total load imposed on the vehicle electrical system and power train by various accessories installed on the vehicle. Most active vehicle components are directly controlled by one of a group of autonomous, vocational controllers, which include a gauge cluster 14, an engine controller20, a transmission controller 16, an auxiliary instrument and switch bank 12, and an antilock brake system (ABS) controller 22, all of which are connected to ESC 30 over a serial data bus 18. The autonomous controllers include local data processing and programming and are typically supplied by the manufacturer of the controlled component. Serial data link 18 is a twisted pair cable constructed in accordance with SAE standard J1939 and is externally accessible via a diagnostic port 36. Although the autonomous controllers handle many functions locally and are functionally difficult without reference to ESC
30, they report data to ESC 30 and can receive operational requests from ESC
30.
A second serial data link 42 extends from ESC 30 back to a remote interface module 40. Remote interface module 40, similarly to the autonomous controllers, provides local control signals to electrical devices constituting or controlling loads installed on vehicle 13. While remote interface module 40 has data processing capability, it typically includes minimal local programming and is dependent on and functionally specified by signals received over the second serial data link 42 from ESC 30 for operation. Hence RIMS 40 are herein termed dependent controllers.
The loads imposed on vehicle 13 systems controlled by electrical control system 30 are usually electrical loads, however, they may include electronicallycontrolled engagement of mechanical devices to the power train of vehicle 13. Gear selection in an automatic transmission would be an example of such an arrangement. Other electrically controlled nonelectrical loads can include control of a clutch for an air conditioning compressor, or actuation of pumps driven by the vehicle drive train. The load management program can, depending on power demands by components, including accessories controlled by a RIM 40, request increased power output from the engine through engine controller 20.
Gauge cluster 14, transmission controller 16 and engine controller20 all communicate with electronic system controller 30, which also monitors inputs received from the auxiliary instrument and switch bank 12, over the serial communication link in harness 18. Electronic system controller 30 may be programmed to override the normal response characteristics of the gauge cluster 14, transmission controller 16 and engine controller 20, should electrical and mechanical loads exceed the capacity of the vehicle, should requests conflict with one another, and under other circumstances.
A RIM 40 is a general purpose control interface allowing the attachment of various accessories to vehicle 13. RIM 40 provides a plurality of ports providing for each of the following: analog inputs; analog outputs; digital inputs; and digital outputs. Characterizationof a particularport as, for example, an output port, does not necessarily mean that it functions exclusively as an output port. For example, an output port may include voltage drop sensing elements, current flow sensing elements, or both, allowing determination by ESC
30 of whether, for example, a bulb in a lamp connected to the output port is operative, or whether a short circuit condition exists in an attached device.
Fig. 2 is a schematic illustration of the vehicle control system 10.
Electrical system controller 30 communicates with local vocational controllers over one of two major SAE J
1939 serial data links 18 and 42.
The J 1939 standard provides for both a open protocol and a proprietary protocol, which differ in the formatting of information transmitted over the serial data links. Accordingly, serial data links 18 and 42 may use the same or different communication protocols. Controllers for substantially common vehicle components such as transmissions, engines and the like communicate with ESC 30 over serial data link 18, which utilizes a open protocol. A diagnostic connector 36 taps into serial data link 18 over which portions of the programming of ESC 30 may be overwritten. In the illustrated embodiment three remote interface modules are defined by ESC
over serial data link 42 to function as a remote power switch 40(A), a remote engine controller 40(B) and a remote air control system 40(C). The specific functions of the several remote interface modules are unimportant and are given as examples only. Disposition of the control of major vehicle drive train components, the vehicle gauge cluster and the diagnostic port 36 onto serial data link 18, and the provision 30 of a second serial data link 42 for carrying communication among the definable, dependent controllers (remote interface modules 40) segregates major vehicle elements in a protected partition via link 18 which is isolated from operator defined functionality implemented over serial data link 42.

ESC 30 also provided from monitoring several bi-state switches in a group of switch banks 51 over a relatively low baud rate SAE J1708 data link 52. ESC 30 can also be directly connected to several devices and sensors directly, which are grouped as discrete outputs 53 and discrete inputs 55.
Fig. 3 is a block diagram of the various elements of ESC 30. ESC 30 includes a fixed number of interface connections for reading bi-state (i.e. onloff) switches. These inputs are appropriate for reading warning light sensors that typically provide a vehicle ground connection to indicate that the sensor is in an active state. An open circuit connection is provided by the sensor to indicate an inactive state. Another collection of inputs labeled analog inputs. These inputs are subject to sampling, analog to digital conversion and storage as a representative binary value in volatile random access memory section 63 of memory 60 for further processing.
A plurality of discrete output interfaces may include low power relay driver connections that are capable of activating an electro-mechanicalrelay device located eisewhereon the vehicle and into the vehicle 1 S power distribution system (not shown). ESC 30 also provides high power solid state output channels. The high power output channels or power switches can handle up to a maximum of ten to twenty amperes at a battery voltage level of 14 volts. The direct input and output channels may be functionally defined by configuration programming of ESC 30. If the number of channel interfaces is insufficient, one or more RIMs 40 are added to private serial data link 42.
ESC 30 has three serial data interfaces including those to the two J1939 serial data links 18 and 42.
The J1939 serial data links operate at 250K baud data rates and, as described above, provide data communication between and among the major power train component autonomous controllers and ESC 30 on link 18 and between the dependent controllers and ESC 30 on link 42. The Siemen C167 Integrated Circuit provides two J1939 ports which are independently accessible and of which one is connected to the private J1939 link 42. The public J1939 link 18 provides connection to the autonomous controllers. In this way the definable RIMs 40 are segregated from the autonomous controllers, protecting the autonomous controllers from programming errors or faults occurring with respect to RIMs 40.
Program memory 69 and most of the addresses of configuration data memory 65 are preferably constructed of flash memory allowing reprogramming of ESC 30 from diagnostic port 36 if required. Program memory 69 preferably requires high input voltages for rewriting, or is otherwise relatively protected compared ko configuration data memory 65. ESC 30 also functions as a data gateway between serial data link 18 and serial data link 42. Serial data link 52 is a 9600 baud link in accordance with the SAE 1708 protocol. Volatile random access memory 63 provides a scratch pad for data from dependent controllers and sensor inputs.
Boot-strap memory 67 loads the core operating program and configuration data.
A central processing unit can address of system memory for execution of the core program and utilization of the configuration data.

5 The program stored in program memory 69 is not typically changed to accommodate the functional definition of either the ports of ESC 30 or Rills 40. The program is event interruptible, looping algorithm which relies entirely on data tables stored in the configuration data memory section 65 to implement specific functionality on any physically undefined interface or port of ESC 30 or a RIM 40. The data tables can be unique to a given vehicle, and relate port addresses to particular functionality and provide for vehicle response under 10 defined conditions.
A RIM 40 may be constructed using digital signal processors or equivalent circuit elements. The methods of programming a digital signal processorto implement any number of circuit elements is well known in the art. ESC 30 must reliably implement various functions at particular ports of the RIM 40 and accordingly a standardized, expandable addressing scheme for each dependent controller and its respective IIO interfaces are provided.
Fig. 4 is a detailed schematic illustration of a physical layer for the invention. ESC 30, located on the cabin side of firewall 92, communicates with engine controller 20, transmission controller 16 and anti-lock brake system 22, and gauge display 14, primarily over serial data link 18.
Selected bi-state switches in engine controller 20, transmission controller 16 and ABS 22 may be controlled or monitored over serial data link 52.
Serial data link 42 provides communication between four dependent controllers or remote interface modules, on which ESC 30 implements an air solenoid drive 40(D), a hydraulic solenoid drive 40(E), a non-specified controller40(F) and a controllerfor remote lamps 40(G). ESC 30 is directly connected to heater controls 75, steering wheel switches 71, and a driver control module 73 handling a plurality of other switches. The direct interfaces implemented by ESC 30 are also functionally defined by configuration programming.
Fig. 5 illustrates a possible physical layer for a vehicle control system including an ESC 30, a plurality of RIMs 40, and a plurality of autonomous controllers on a truck 13. One RIM
40 is located at the exterior of cab 113, providing a pluralityof interfaces in the rear portion of truck 13. A
coach or vehicle body builder can define the interfaces to control a variety of optional or accessory equipment.
The coach or vehicle body builder uses programming specifications to design a configuration data base to give the dependent controller functionality. A second RIM 40 may be positioned forward of the fire wall 92 on vehicle 13. So positioned the second RIM 40 is conveniently situated to equipment added to the front end of a vehicle such as special lights or a positionable plow.
The invention enables implementation of a vehicle communications and control system having a uniform, but scalable, physical layer. Autonomous controllers, dependent controllers, central electrical system controllers and intenronnecting data links can be physically iden~cal from one vehicle to another across groups of vehicles of increasinglydifferentiated vocational requirements. The only physical difference, in many cases, will be the actual physical position on the vehicle which, from an electronic standpoint, provides a substantially uniform physical layer from vehicle to vehicle. Uniformity and scalability of the dependent controllers helps minimize the number and variety of local controllers required in the physical layer to implement vehicle vocations. The scalable implementation through the use of scalable, functionally generic, local controllers, and definable interfaces on the electrical system controller substantially relieves the communications and control system of input and output resource limitations. Scalability is further enhanced by providing a core program executable on scalable data tables which define the functionality of IIO ports.
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.

Claims (8)

WHAT IS CLAIMED IS:

1. A control system for a vehicle, comprising:
a non-generalized physical layer including, a system controller having memory for the storage of programs and data, a plurality of specialized local controllers and a data bus connecting the system controller with the specialized local controllers for the two way communication of information;
a generalized physical layer including, a second data bus connected to the system controller, and at least a first generic local controller having a plurality of standard ports for the connection of controlled devices, the first generic controller being connected to the second data bus to receive data from and transmit data to the system controller, the first generic controller and one or more of the standard ports assuming a functional state in response to instruction data received over the second data bus from the system controller;
configuration data stored in the memory specifying functionality for at least the first generic local controller and for at least one standard port of the generic local controller;
a core operating program stored in the memory executable by the system controller on the configuration data for the generic local controller in the generalized physical layer to construct instruction data for implementing a functionality on the generic local controller; and means for transmitting the instructions as data to the generic local controller over the second data bus.

2. The control system for a vehicle according to claim 1, wherein the core operating program is generalized to operate on configuration data defining functions for a plurality of generic local controllers.

3. The control system for a vehicle according to claim 2, wherein each generic local controller has a plurality of external connection interfaces for coupling to devices, the external connection interfaces being definable through the instruction data.

4. The control system for a vehicle according to claim 3, wherein the system controller is accessible through an external interface by which the core operating program and configuration data may be written to the memory.

5. The control system for a vehicle according to claim 4, further comprising:
a plurality of switch devices; and a third data bus connected between the electrical system controller and the plurality of switch devices allowing the electrical system controller to read the state of the switch devices.

6. The control system for a vehicle according to claim 5, the electrical system controller further including gateway means for translating data from the second data bus for application to the first data bus.

7. The control system for a vehicle according to claim 6 further comprising a plurality of differentiated electrical and mechanical loads connected for control to the specialized local controllers and generic local controllers.

8. The control system for a vehicle according to claim 7; wherein the generalized physical layer is uniform and scalable.