TOF Sensor Array Safety Monitoring for Dusty Woodworking Machines

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Solution Overview

Problem

Existing safety laser scanners used in monitoring areas around machines, such as woodworking machinery, often produce false positives due to particle pollution like dust and debris, leading to unnecessary machine stoppages.

Innovation Solution

A protective device featuring a time-of-flight (TOF) sensor array and a controller that defines a safety area within the sensor's field of measurement, detects objects, and generates a safety output to control the machine's operation, thereby reducing false positives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If traditional safety scanners detect particles, then particle presence is detected, but machine operation stops unnecessarily

Engineering Contradiction:

Improveparticle detection capabilityVSAvoidmachine operation continuity

Core Design Contradiction:

Difficulty of detecting and measuringVSProductivity

Solution Approach 1:

The patent applies different evaluation criteria to different sensing zones. Instead of treating all detected objects uniformly, the system analyzes the spatial distribution, size, and position of detected objects within specific zones. This local quality approach allows the system to identify particle pollution patterns (small, scattered detections) versus actual safety hazards (larger, more defined objects in critical zones), enabling selective response that maintains productivity while ensuring safety.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the detection parameters from simple presence/absence detection to time-of-flight based distance measurement. By measuring the time it takes for light to travel to and from detected objects, the system obtains depth information that helps distinguish particles (short, inconsistent flight times) from actual objects (consistent, measurable distances). This parameter change enables intelligent filtering of particle detections while maintaining sensitivity to real hazards.

Inventive Principle:

Principle #35Parameter changes

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 effectively reduces the number of false positives caused by particle pollution, enhancing the reliability of safety monitoring and minimizing unnecessary machine stoppages.

Implementation Method 1

a sensor array having a plurality of time-of-flight (TOF) sensors arranged to form a sensible field for TOF measurements

Methodology Applied

Scientific EffectTime of flight: Time of Flight

Data Source

PatentUS20250091169A1Protective device with time-of-flight array for providing safety monitoring of a machine and related methods

Publication Date: 2025.03.20 DATALOGIC IP TECH

AI summary

The disclosure includes a protective device for a machine, a method of operating a protective device, and a protective system including the protective device and the machine. The protective device may include a sensor array disposed on the machine. The sensor array may have a plurality of time-of-flight (TOF) sensors arranged to form a sensible field for TOF measurements, and a controller configured to define a safety area within the sensible field, detect an object within the sensible field, and generate a safety output that controls an operation of the machine in response to the object being detected within the safety area. The machine may include woodworking machines or other machines having debris or particles in the surrounding environment during operation.