Rammer Fall Detection Sensor Using Wave Pattern Matching

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Solution Overview

Problem

Conventional fall detection sensors struggle to accurately determine if a rammer has fallen during operation due to its large vibrations and impacts, often leading to erroneous determinations.

Innovation Solution

A fall detection sensor system that includes acceleration sensors for three axes, low-pass filters to remove high-frequency noise, integrators to process signals, and comparators to compare signal patterns with stored sample waves, ensuring accurate fall detection and immediate motor shutdown.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an acceleration sensor is used to detect fall state by monitoring gravitational acceleration changes, then fall detection capability is provided, but measurement precision deteriorates due to complex motion acceleration components from vibrations and impacts

Engineering Contradiction:
Improvefall detection accuracyVSAvoidacceleration detection precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The acceleration detection is divided into three independent axes (X, Y, Z directions), allowing separate analysis of gravitational acceleration components along each axis. This segmentation enables the system to isolate the gravitational signal from vibration and impact noise by analyzing directional components individually.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Fall sample waves and non-fall sample waves are stored in advance in the storage unit based on gravitational acceleration patterns detected during normal operation. These pre-stored reference patterns are used for comparison during actual operation, enabling rapid and accurate fall detection without complex real-time analysis.

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If simple acceleration threshold comparison is used for fall detection, then device complexity is reduced, but measurement precision deteriorates due to erroneous detection during vibrations

Engineering Contradiction:
Improvedetection system complexityVSAvoidfall detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

Sample waves representing fall and non-fall conditions are pre-collected and stored during normal operation. These reference patterns capture the characteristic acceleration signatures of different states, allowing the system to perform accurate classification during operation through simple pattern matching rather than complex real-time analysis.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system creates copies of actual acceleration wave patterns during normal operation and stores them as reference samples. During detection, the current acceleration pattern is compared against these stored copies to determine fall state, replacing complex threshold-based logic with pattern recognition.

Inventive Principle:
Principle #26Copying

3Measurement precision

If multiple processing steps (low-pass filter, integrator, comparators) are added to improve fall detection accuracy, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvefall detection accuracyVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs signal processing and pattern classification in advance by storing representative sample waves during normal operation. This preliminary action creates a reference library that simplifies real-time detection to a straightforward comparison operation, reducing the complexity of ongoing signal processing while maintaining high accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of implementing complex real-time analysis algorithms, the system copies and stores actual acceleration patterns from normal operation as reference samples. The detection process then simply compares current patterns against these stored copies, achieving high precision through pattern recognition rather than complex computational processing.

Inventive Principle:
Principle #26Copying

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 effectively differentiates between fall and non-fall states with high accuracy, avoiding erroneous determinations caused by vibrations and noise, and ensures timely motor shutdown.

Implementation Method 1

an acceleration sensor configured to detect a gravitational acceleration and a motion acceleration with respect to a sensitivity direction, and to output an electrical signal having a level proportional to a magnitude of the detected acceleration

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3486372B1Fall-down detection sensor for rammer
Publication Date: 2021.03.03 MIKASA SANGYO KK
  • EP3486372B1 patent drawingFigure 1

AI summary

Provided is a fall detection sensor for rammer capable of determining a fall state of a rammer, that operates with a large vibration and impact, with high accuracy, and stopping a motor (an engine or the like) immediately. The fall detection sensor for rammer includes an acceleration sensor (2), a low-pass filter (3), an integrator (4), a first comparator (5), a second comparator (6), and control means (7). The second comparator (6) compares wave patterns of input signals (x' - z') with a plurality of types of of fall sample waves (FW) and non-fall sample waves (NFW) stored in advance. The second comparator (6) outputs a fall detection signal (fs) upon determining that the rammer has fallen when the similarity with the fall sample wave (FW) exceeds a threshold, and the second comparator (6) outputs a non-fall signal (nfs) upon determining that the rammer has not fallen when the similarity with the non-fall sample wave (NFW) exceeds a threshold.