Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Transmission control
Reexamination Certificate
2000-12-28
2002-08-13
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Transmission control
C701S054000, C701S055000
Reexamination Certificate
active
06434465
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for controlling/regulating a process in a motor vehicle, in particular a combustion process, gear-shifting process, or braking process, with the help of a characteristics grid map. The characteristics map is defined by several performance quantities of the process, which is to be controlled or regulated, and is represented by data points that have corresponding characteristics-map values. The control/regulation of the process occurs in consecutive control cycles. In one control cycle, at least one characteristics-map value is determined from the characteristics map for an operating point of the process. In addition, adjacent data points, which define an interpolation range in which the operating point lies, are initially determined, and then interpolation is performed between the data points. The present invention also relates to a control/regulating device for implementing this method.
BACKGROUND INFORMATION
A central problem in realizing control systems or regulating systems, in particular in automotive engineering, is simulating characteristics of the subsystems, which are to be controlled or regulated, in a computing device of the control/regulating device. For example, from these internal simulations, important internal state variables, which cannot be directly measured online or are not measured for cost reasons, can be determined for a controller, or the values determined by the simulation are used for the direct control or regulation of a process.
For representing a model in a control/regulating device, there are two fundamentally different conventional approaches:
simulating the relevant physical-technical system characteristics using a mathematical model (for example a differential equation system); and
directly storing pertinent system data as a function of the relevant performance quantities (characteristics map).
For use in a motor vehicle, a characteristics map has the advantage of a low computing time requirement, since complicated model calculations are not necessary. Instead, the values corresponding to a specific operating point of a process can be taken directly from the characteristics map. The characteristics map also has advantages in regards to simplifying the application. In a model representation that has analytical equations that describe physical contexts, the applications engineer generally must have extensive knowledge of the model structure to be able to perform a targeted optimization. Since the influence of the parameters, which are to be adapted, usually extends to additional areas of the “address space” and a more or less strong coupling of the influences exists, a lengthy, iterative search for the optimum parameter combination may be necessary in some instances. By contrast, every data point adjustment in a characteristics-map representation has a clearly defined, strictly limited local effect. Therefore, detailed model knowledge or an iterative procedure are not necessary. A systematic, standardizable adjustment is possible and can even be automated in some instances.
For these reasons, using characteristics maps for controlling or regulating processes in mass-produced control/regulating devices is already widespread today. In motor vehicles, characteristics maps are used, for instance, for injection and ignition, and for precisely managing additional modern engine management system tasks. Characteristics maps are also widely used for providing complex model information in safety systems such as anti-lock braking systems (ABS), anti-spin regulation (ASR), and other systems, which ensure driving stability and/or safety, and/or influence braking action, as well as in numerous other applications such as automated transmissions.
The characteristics maps used can be one-dimensional (characteristic curves) or two or more-dimensional. Since the demands for functionality and precision in the processes, which are to be controlled or regulated, are constantly rising, it will be increasingly necessary in the future to link more than two performance quantities in a characteristics map. Moreover, an exact coordination of performance quantities, which influence one another, such as injection quantity, ignition-advance angle, acceleration enrichment, etc. will be necessary.
The characteristics map of the present method for controlling/regulating a process in a motor vehicle is designed as a characteristics grid map. The data points, which represent a characteristics grid map, are usually arrayed equidistant to each other. However, there are conventional characteristics grid maps, in which the data points are placed in the ranges of the input variables, in which ranges the function to be stored changes dramatically. To this end, the input variable is non-linearly mapped on the characteristics map using a data-point table having non-equidistant data-point distribution. Equidistant data-point distribution can then be expected again within the characteristics map.
German Patent No. 34 38 781 describes a method using a characteristics grid map to help control/regulate a process in a motor vehicle. However, the method described therein is limited to a two-dimensional characteristics grid map, i.e. to a characteristics grid map that is defined by two performance quantities of the process. German Patent No. 34 38 781 describes a square interpolation (bilinear interpolation) in FIG.
3
and the corresponding figure description, and a triangular interpolation in FIG.
4
and the corresponding figure description.
Within the framework of a square interpolation, four adjacent data points are first determined that define an interpolation square in which an operating point of the process to be controlled or regulated lies. Subsequently, bilinear interpolation is performed between the data points. In triangular interpolation, three adjacent data points are first determined that define an interpolation triangle in which the operating point of the process lies. Subsequently, interpolation is performed between the data points within the bounds of non-linear interpolation. The described square interpolation has the disadvantages that a relatively large program size must be made available and that producing the characteristics-map value corresponding to the operating point necessitates a relatively long running time. In contrast, the described triangular interpolation has the advantage of a smaller program size with respect to the square interpolation, and the disadvantage of a longer running time. Yet above all, program size (a cost factor) and the processing speed of a processing unit play a major role in the application of a conventional method for controlling/regulating a process in a motor vehicle. Furthermore, the described triangular interpolation is limited to use in a characteristics grid map that has equidistant data-point distribution at a distance of the power of two.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method and device for controlling/regulating a process in a motor vehicle that are universally employable for characteristics maps of any dimension and data-point distribution, that have a reduced computational time for interpolation for constant or not significantly worsening interpolation quality, and that have an interpolated characteristics-map surface that has a steady pattern without discontinuities.
The object of the present invention is achieved by a method and device for controlling/regulating a process in a motor vehicle that determines the characteristics-map value for the operating point within the framework of a linear interpolation from a minimum number of data points. The number of data points resulting from the number of performance quantities of the process, which define the characteristics map, plus one.
The linear interpolation can be performed using, for example, an interpolation approach involving barycentric coordinates. Barycentric coordinates are coordinates related to the interpolation range that determine corresponding weighting values
Hess Werner
Schmitt Manfred
Kenyon & Kenyon
Marc-Coleman Marthe
Robert & Bosch GmbH
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