Capacitive Trunk Lid Detection System for Collision Avoidance

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Solution Overview

Problem

Current systems for automatically actuated vehicle trunk lids lack effective safety measures to prevent injuries from accidental closure, as they only react after a person or object is trapped, and existing solutions like tactile sealing strips are insufficient in preventing collisions.

Innovation Solution

A capacitive detection system with field generation and detection electrode structures integrated into the trunk lid sealing device, capable of modulating voltage and frequency to detect approaching human limbs and adjust the movement mechanism to avoid collisions, using redundant sensor systems and frequency analysis to monitor the closing and opening processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If capacitive detection system with modulated voltage and frequency is implemented, then detection precision is improved, but device complexity increases

Engineering Contradiction:
Improvedetection precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines field generation electrode structure and detection electrode structure into a single integrated capacitive detection system within the sealing device. This merging of functions into one unified system enables precise detection of approaching objects through capacitance changes while avoiding the need for separate complex detection and actuation systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system modulates voltage and frequency parameters of the electric field to optimize detection precision. By changing these electrical parameters dynamically, the system can detect subtle capacitance variations caused by approaching human limbs or objects, achieving high measurement precision without requiring complex mechanical detection mechanisms.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If redundant sensor systems are used to ensure safety, then reliability is improved, but device complexity increases

Engineering Contradiction:
ImprovereliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The capacitive detection system serves multiple functions: it detects approaching objects, determines their material properties (conductive vs. non-conductive) through capacitance analysis, and triggers appropriate safety responses. This multi-functionality provides redundant safety monitoring without requiring entirely separate sensor systems, thereby improving reliability while controlling complexity.

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

Solution Approach 2:

The patent replaces complex mechanical safety systems with an electrical capacitive detection system. Instead of using multiple mechanical switches or physical sensors, the system uses electrical field interactions to detect objects and trigger safety mechanisms, achieving high reliability through electrical redundancy rather than mechanical complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If automatic closing function is implemented, then ease of operation is improved, but object-affected harmful factors increase

Engineering Contradiction:
Improveease of operationVSAvoidinjury risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary detection of approaching objects before the trunk lid completes its closing motion. By detecting conductive objects (human limbs) in advance through capacitance changes and classifying their material properties, the system can interrupt the closing sequence before injury occurs, maintaining automatic operation while preventing harmful effects.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The capacitive detection system continuously monitors the closing area and provides real-time feedback to the control unit. When an approaching conductive object is detected and classified as a safety risk, the system immediately feedbacks this information to stop or reverse the closing motion, thereby maintaining ease of automatic operation while eliminating injury risk through continuous monitoring and responsive control.

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 system reliably detects approaching objects and adjusts the movement of the trunk lid to prevent injuries, allowing for safe and automatic operation of vehicle flaps while reducing the risk of collisions and damage.

Implementation Method 1

both the closing edges and other dangerous areas of a trunk and the moving vehicle parts (lids) are monitored and subjected to alternating electric fields

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Implementation Method 2

an approximation state characterized by the vital object approaching the moving component is detected continuously or at sufficiently short time intervals on the basis of field-electrical interaction effects

Methodology Applied
Scientific EffectElectric field interaction: Electric Field

Implementation Method 3

a voltage that is modulated with respect to the phase position and voltage difference relative to the detection electrode structure and/or the field preparation structure can be applied to it

Methodology Applied
Scientific EffectVoltage modulation: Phase Modulation

Data Source

PatentEP1979202B1Method and monitoring system for closing covers
Publication Date: 2020.05.06 MICROCHIP TECH GERMANY II
  • EP1979202B1 patent drawingFigure 1a
  • EP1979202B1 patent drawingFigure 1b
  • EP1979202B1 patent drawingFigure 2a~2b

AI summary

The invention relates to a method and a monitoring system for automatically actuated, in particular power-driven closing covers, for example boot lids of motor vehicles. The invention also relates to a method and a detection system for detecting the presence of objects per se. The aim of the invention is to provide solutions for the implementation of a reliable safety system. According to the invention, this is achieved by a detection system comprising a modulation unit for generating an alternating voltage, which is applied between a first output and a second output on the modulation device, a field generation structure that is coupled to one of the outputs in order to generate an extensive excitation field and a detection device comprising a detection electrode structure for detecting a field-electric effect in a detection area that extends along the electrode structure, the field generation structure and the detection electrode structure being located in the vicinity of one another and the detection electrode structure and the field generation structure being shielded from one another, in such a way that when the excitation field and the detection area are bridged by an object to be detected, a voltage event that can be classified as indicating a presence is induced in the detection electrode structure.