Autonomous Driving Mode Switch Circuit With Resistance Fault Detection

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Solution Overview

Problem

Existing control systems for autonomous vehicles lack the ability to detect failures in the electronic mounting of switches that control the autonomous driving mode, which is critical for ensuring safety and reliability.

Innovation Solution

A selection device for autonomous vehicles that includes at least one control switch connected in series with a resistance, a safety resistance connected in parallel, and an electrical assembly that allows the on-board computer to detect switch states and potential failures by measuring equivalent resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two switches are used to control autonomous mode activation, then safety against involuntary activation is improved, but the ability to detect system failures deteriorates

Engineering Contradiction:
Improvesafety against involuntary activationVSAvoidsystem failure detection
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent implements a feedback mechanism where the computer continuously monitors the electrical assembly's resistance characteristics. The system measures the equivalent resistance between the first potential point (connected to DC voltage) and the second potential point (connected to ground) to detect the state of switches and identify failures such as open circuits or short circuits in the electrical assembly, providing continuous feedback on system health.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces an intermediary measurement mechanism using resistance monitoring as a mediator between the switch control system and the computer. By measuring the equivalent resistance of the electrical assembly, the system can indirectly detect switch states and failure conditions without requiring direct complex signaling from each switch, thus enabling failure detection while maintaining the two-switch safety configuration.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple switches are used for mode selection, then control safety is improved, but the complexity of the electrical assembly increases

Engineering Contradiction:
Improvecontrol safetyVSAvoidelectrical assembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the resistance measurement mechanism multi-functional, serving both as a normal operational parameter and as a failure detection mechanism. The same electrical paths used for switch control also serve as the measurement paths for detecting switch states and failures, eliminating the need for separate dedicated failure detection circuits and reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent utilizes changes in electrical resistance parameters to encode multiple states of the electrical assembly. By monitoring the equivalent resistance value, the system can distinguish between different switch configurations (normal operation) and various failure modes (open circuit, short circuit), allowing a single measurement parameter to convey multiple pieces of diagnostic information and simplifying the control architecture.

Inventive Principle:
Principle #35Parameter changes

3Difficulty of detecting and measuring

If resistance measurement is used to detect switch states, then detection capability is improved, but the risk of electrical failures increases

Engineering Contradiction:
Improveswitch state detection capabilityVSAvoidelectrical failure risk
Core Design Contradiction:
Difficulty of detecting and measuringVSObject-affected harmful factors

Solution Approach 1:

The patent implements beforehand cushioning by continuously monitoring the electrical assembly's resistance characteristics during normal operation. This allows the system to detect early signs of degradation or emerging failures (such as gradual resistance changes indicating loose connections or deteriorating components) before they develop into complete failures, enabling preventive maintenance or safe shutdown procedures.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The system uses feedback from resistance measurements to continuously assess the health of the electrical assembly. By comparing measured resistance values against expected ranges for different switch states and operational conditions, the computer can identify anomalies that indicate developing failures, providing feedback that triggers appropriate responses to mitigate the risk of catastrophic electrical failures.

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution provides enhanced security by enabling the detection of switch states and potential failures, such as short circuits or open circuits, thereby ensuring the reliability of the autonomous driving mode control system.

Implementation Method 1

the equivalent resistance of the electrical assembly makes it possible to determine on the one hand whether the switch is closed or open and on the other hand a potential failure of said electrical assembly

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP4330086B1Device for selecting the driving mode of an autonomous motor vehicle
Publication Date: 2025.04.16 NISSAN MOTOR CO LTD
  • EP4330086B1 patent drawingFigure 1
  • EP4330086B1 patent drawingFigure 2
  • EP4330086B1 patent drawing

AI summary

Device (1) for selecting the driving mode of an autonomous motor vehicle, having an electrical assembly (100) in which a switch (10, 20) is associated in series with a first resistor (11, 21), a safety resistor (30) being connected in parallel with said switch (10, 20) and with said associated first resistor (11), said electrical assembly being connected firstly to a DC voltage source (41) of a computer (40) and secondly to a ground (42) of the computer (40), such that the equivalent resistance of the electrical assembly (100) makes it possible to determine firstly whether the switch (10) is closed or open and secondly a potential fault with said electrical assembly (100).