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DE-102024133039-A1 - Methods for storage-optimized data storage in a memory

DE102024133039A1DE 102024133039 A1DE102024133039 A1DE 102024133039A1DE-102024133039-A1

Abstract

Method for memory-optimized storage of data in a control unit, wherein the control unit has a non-volatile memory, wherein the data are recorded in the form of a histogram over a certain period of time, characterized in that when the control unit is switched off, a function with coefficients is applied to map the shape of the histogram and only the coefficients are stored in volatile memory until the next start of the control unit.

Inventors

  • Christian Boehmer
  • Max Hierlwimmer
  • Markus Widmann

Assignees

  • Magna PT B.V. & Co. KGaA

Dates

Publication Date
20260513
Application Date
20241112

Claims (5)

  1. Method for memory-optimized storage of data in a control unit, wherein the control unit has a non-volatile memory, wherein the data are recorded in the form of a histogram over a certain period of time, characterized in that when the control unit is switched off, a function with coefficients is applied to map the shape of the histogram and only the coefficients are stored in the volatile memory until the next start of the control unit.
  2. Procedure according to Claim 1 , characterized in that the function is a polynomial function.
  3. Procedure according to Claim 1 or 2 , characterized in that, upon restarting the control unit, the stored coefficients, together with the applied function, serve to restore the shape of the histogram.
  4. Method according to one of the preceding claims, characterized in that the control unit serves to record usage statistics over a longer period of time and over repeated switching on and off.
  5. Method according to one of the preceding claims, characterized in that the control unit monitors a drive component of a vehicle.

Description

The invention relates to a method for memory-optimized storage of data in a control unit, wherein the control unit has a non-volatile memory, and wherein the data is recorded in the form of a histogram over a specific period of time. State of the art In computer science and software engineering, a data structure is an object used to store and organize data. It is considered a structure because the data is arranged and linked in a specific way to enable efficient access to and management of the data. Data structures are characterized not only by the data they contain, but above all by the operations on that data that enable and implement access and management. An array is the simplest data structure used. It stores multiple variables of the same basic data type. Individual elements are accessed via an index. Technically, this index is the value added to the array's starting address in memory to obtain the object's address. The only necessary operations are indexed storage and indexed read, which allow direct access to any element of the array. In the one-dimensional case, the array is often called a vector, and in the two-dimensional case, a table or matrix. However, arrays are by no means limited to two dimensions; they can be used in any number of dimensions. A special case is the mapping table, in which the stored data is accessed not via a numerical index, but via a key. During the operation of an embedded control unit within a system, e.g., an electric drive, automated transmission, etc., operating data such as temperature dwell times and mechanical load data of shafts or gears are frequently recorded. These are typically implemented as counters that, for example, count the dwell time within a defined temperature range. Recording this dwell time/load data across the entire defined value range generates a histogram. A histogram is a graphical representation of the frequency distribution of scaled variables. It requires dividing the data into classes, which can have a constant or variable width. Adjacent rectangles are drawn, each with a width equal to that of its respective class. The area of each rectangle represents the relative or absolute frequencies of that class. The height of each rectangle then represents the relative or absolute frequency density, i.e., the relative or absolute frequency divided by the width of the corresponding class. For a vehicle control unit, recorded/counted dwell times, wheelset rotations, etc., are written to an EEPROM memory before the control unit shuts down. When the control unit restarts, the stored data is read back so that counting can continue from there. A defined storage space within the EEPROM must be reserved for each class of the histogram to ensure that the value range of the data type is sufficient for the entire product lifecycle. Especially with load data, the storage requirements quickly become very high. DE 11 2009 0000 047 B4 This relates to a vehicle-side control unit that controls an operation of a vehicle-side automatic device, and a method of writing a control program and/or reference data used during program execution to the vehicle-side control unit. In the case that compressed "control data" is transmitted to the microcomputer using a second type of data transmission frame, a writing tool compresses the "control data," and when the total amount of compressed data exceeds the "first setting amount," the writing tool divides the compressed data by a "setting amount," so that data transmission frames of a second type are formed from the divided compressed data, and the writing tool stores the formed data transmission frames. The boot program, which starts immediately after power-on, includes a program that decompresses compressed "control data" within a second type of data transmission frame. This decompression program is then used to decompress the compressed "control data." In other words, the decompression program is used to restore the compressed "control data." The object of the invention is to propose a vehicle-side control unit that has an optimized memory, so that the storage space can be reduced. Description of the invention The task is solved using a method for memory-optimized storage of data in a control unit, wherein the control unit has non-volatile memory, wherein the data is recorded in the form of a histogram over a certain period of time, wherein when the control unit is switched off a function with coefficients is applied to map the shape of the histogram and only the coefficients are stored in the volatile memory until the next start of the control unit. The invention describes a method for compressing recorded operational or load data to significantly reduce the required EEPROM memory. With reduced memory requirements, a larger number of storable histograms are possible with the same EEPROM memory size. This also allows for the storage of a larger number of dimensions with the same EEPROM memory size. In one embodiment, the func