Dual-Core Microcomputer Steering Error Segmentation

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Solution Overview

Problem

Existing electric power steering systems with single-core microcontrollers face sudden shutdowns due to undiagnosed errors, leading to comfort restrictions for drivers, as they lack effective mechanisms to differentiate between calculation and systematic software errors, necessitating a transition to a safe state.

Innovation Solution

A dual-core microcomputer architecture with parallel processing of control and monitoring paths and a core comparator to identify errors, allowing a transition to emergency operation mode with reduced steering assistance to ensure safe driving while maintaining some functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the system switches off immediately upon detecting a difference between control path and monitoring path results, then system safety is improved, but driver comfort deteriorates due to sudden shutdown

Engineering Contradiction:
Improvesystem safetyVSAvoiddriver comfort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The error detection and response system is segmented into multiple levels: the core comparator performs granular comparison of individual calculation steps, while the functional-level comparator assesses overall functional results. This segmentation allows the system to distinguish between transient calculation errors (detected at granular level) and systematic software errors (detected at functional level), enabling differentiated responses that maintain safety while avoiding unnecessary shutdowns

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts its response based on the type of error detected. Instead of a static immediate shutdown for all errors, the system transitions to an emergency operation mode with limited functionality when systematic errors are detected, allowing continued safe operation with reduced comfort features. This dynamic response optimizes both safety and comfort based on the specific error condition

Inventive Principle:
Principle #15Dynamics

2Reliability

If diverse algorithms are implemented for control path and monitoring path, then systematic software error detection is improved, but device complexity increases

Engineering Contradiction:
Improvesystematic error detectionVSAvoidalgorithm complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The core comparator acts as an intermediary between the control path and monitoring path, performing granular comparison of individual calculation steps before the results reach the functional-level comparator. This intermediary comparison mechanism enables the system to detect and filter out transient calculation errors, allowing the diverse algorithms to focus on detecting systematic software errors without being triggered by normal computational variations

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system adds a temporal dimension to error detection by comparing not just the final results but also the intermediate calculation steps across time. The core comparator analyzes granular calculation steps in real-time, while the functional-level comparator assesses overall functional results, creating a multi-dimensional error detection framework that improves systematic error detection without requiring overly complex algorithms

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If the system transitions to emergency operation mode instead of hard shutdown, then driving availability is improved, but steering assistance performance deteriorates

Engineering Contradiction:
Improvedriving availabilityVSAvoidsteering assistance performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

In emergency operation mode, the system implements partial action by providing limited steering assistance rather than full assistance. The emergency program allows the vehicle to be driven safely to a standstill with reduced steering support, accepting degraded performance in exchange for maintaining driving availability. This partial operation enables the system to reach a safe state without complete shutdown

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2755881B1Method for operating an electrical power steering mechanism
Publication Date: 2015.06.03 ROBERT BOSCH AUTOMOTIVE STEERING
  • EP2755881B1 patent drawingFigure 1
  • EP2755881B1 patent drawingFigure 2

AI summary

Computer and function architecture for operating an electrical power steering mechanism characterised in that a control path (202) and a monitoring path (203) designed redundantly thereto are processed more or less in parallel on two assigned cores (Core1, Core2) of a redundant microcomputer (200) and computation differences within the control path (202) or the monitoring path (203) are detected at functional level by means of a comparator (204) and the results of individual calculation steps at granular level are detected by means of a core comparator (205) and upon a detected difference of the comparator (204) at functional level, if the core comparator (205) has not diagnosed a computation error, passes to emergency operation (206), in order to provide the further availability of at least one part of the steering support or the steering function for at least a certain period of time.