Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle subsystem or accessory control
Reexamination Certificate
2002-10-23
2004-04-27
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle subsystem or accessory control
C701S033000, C340S002260, C340S003100, C340S003510, C710S110000, C710S116000, C710S119000, C710S123000, C700S002000, C700S003000, C709S222000
Reexamination Certificate
active
06728618
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for activating a system for controlling and/or regulating operational sequences in a motor vehicle. The system includes several equal-access control units for controlling and/or regulating certain functions in the motor vehicle. The control units each have a volatile memory and a non-volatile memory including a loading routine. They are connected to one another via a time-controlled communications system.
The present invention also relates to a computer program which may be run on a computing unit, in particular a microprocessor, of a control unit for controlling and/or regulating certain functions in a motor vehicle.
Finally, the present invention also relates to a system for controlling and/or regulating operational sequences in a motor vehicle having several equal-access control units for control and/or regulation. Each control unit includes a volatile memory and a non-volatile memory including a loading routine, and are connected to one another via a time-controlled communications system.
BACKGROUND INFORMATION
A plurality of control devices for controlling or regulating the operational sequences in a motor vehicle are provided. These control devices, of which each controls or regulates a particular functional unit of the motor vehicle during operation, are connected to one another via a communications system. The control units are communications users of the system. One known communications system, for instance, is TTP/C (time-triggered protocol, SAE Class C) or FlexRay (a communications system under development by BMW, DaimlerChrysler, Motorola, Philips and Bosch; Information available on the Internet under http://www.flexray-group.com).
Control units may, in principle, be divided into two categories. On the one hand there are the so-called individual control units. These are control units having an individual program. They are applied, for instance, to regulating braking systems (anti-lock brake systems, ABS) or to regulating an internal combustion engine. On the other hand, control units having the same construction are provided, which are used, for example, for regulating electromechanical brakes (EMB; brake-by-wire). In the case of EMB, four control units are provided one for each wheel, which are identically constructed and operated with the same software. The four control devices fulfill the same function, namely, adjusting the braking force according to a setpoint input.
When each individual wheel is regulated, the differences come about only from the local positioning of the control unit. That is the case in a braking force distribution between front and rear axle, and in operating an ABS,ASR (drive slip regulation) or ESP (electronic stabilizing program). In those cases, the control unit has to know to which wheel it is assigned, since wheel-specific setpoint values are to be lined up.
The control units usually have a non-volatile program memory and a volatile memory. In order to simplify the programming of the control units of the system, particularly with respect to a subsequent modification of functional units of a motor vehicle controlled or regulated by the system, that part of the program which is identical for all control units may be stored in a central memory, and from there may be transmitted to the volatile memory of the individual control units, within the framework of activating the system. In the case of a subsequent modification, a program change has only to be made at one central location, namely the central memory.
Distributed systems having a time-controlled communications system are known, for example, from German Published Patent Application No. 197 53 288. They require a common global time base. This is formed with the participation of all the control units logged on to the communications system. It is known, for example, that one may form the global time base by forming the average value of all the local time bases of the control units. The control units ascertain individual differences between their local time base and the global one. In the control units the difference is added to the local time base, and the sum is used as the global time base. The process just described is called synchronization of the control units to the global time base.
However, in the case of systems, known from the related art, having several control units which are connected by a time-controlled communications system, it is difficult to bring about the activation of the system if the data required for the time-controlled communications for all the control units are stored in the central memory.
A method for operating a time-controlled communications system of Motorola is known from its “DSI Bus Standard, Release 1.0”. In this case, in normal operation a master control unit is required, which makes available the global time pulse to the slave control units. In order for the system to remain fully functional even during malfunctioning of the master control unit, the master control unit must be designed to be redundant. This results, however, in considerable additional costs for the hardware that is not used in the normal case. These costs may be saved in the case of systems having equal-access control units as communications users.
SUMMARY OF THE INVENTION
The present invention is based on the creation of a safe and reliable activation of a system for controlling and/or regulating operating sequences in a motor vehicle.
Starting out from the method of the species recited at the outset, the present invention proposes a method having the following method steps to achieve this object:
the system is switched on;
one of the control units temporarily becomes a master control unit;
at least one of the control units has a central memory in which data are stored that are used for the time-controlled communications for all the control units, and, during the activation process of the system, the master control unit coordinating the logging on of the remaining control units to the communications system, in particular the transmission of the data from the central memory via the communications system to the remaining control units; and
the temporary master function of the master control unit is ended upon the expiration of a predefinable time duration or at termination of the activating process.
According to the present invention it is proposed that the distributed system shall be operated using a time-controlled communications system in normal operation with equal-access communications users. Thereby, the system may be scaled and expanded without problem. In order to be able to coordinate the required sequences in the system during the activation process (revving-up), it is proposed that one of the control units temporarily assume the function of master control unit. The remaining control units are treated as slave control units during the activation process. Which control unit is drawn upon as master control unit may be determined at will.
At least one of the control units has a central memory in which data required for the time-controlled communications are stored. Within the framework of the activation of the system, these data are transmitted to the individual control units which have logged on to the communications system, and are there stored, for example, in the volatile memory. The master control unit coordinates the activation process of the system, particularly the reading out of the data from the central memory, and the transmission of the data via the communications system to the control units.
As long as one of the control units assumes the master function, the local time of the master control unit is used as the global time base for the communications system. The remaining control units are synchronized with this local time base. After the expiration of a predefinable time duration (a so-called timeout) or after termination of the activation process of the system, the master control unit gives up its master function again, and becomes an equal-access communications user, in addition to the remaining
Heckmann Hans
Kesch Bernd
Weiberle Reinhard
Broadhead B J
Cuchlinski Jr. William A.
Kenyon & Kenyon
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