Hydraulic Excavator Worker Proximity Detection Using Hybrid RFID and GNSS
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Solution Overview
Problem
Existing systems for detecting workers near work machines, such as hydraulic excavators, often result in excessive alerts due to inaccurate distance and direction measurements, and are prone to errors from environmental factors like sunlight and satellite signal interference.
Innovation Solution
A work machine system incorporating a GNSS receiving device, magnetic field generating device, and worker tags that use both GNSS and magnetic field induction RFID to accurately detect worker proximity, adjusting detection areas based on operational states and positional information to minimize false alerts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If infrared sensors or ultrasonic sensors are used to detect workers, then detection can be performed, but detection accuracy deteriorates due to environmental factors like sunlight, air pressure, and humidity
Solution Approach 1:
The patent replaces optical sensors (infrared) and acoustic sensors (ultrasonic) with RFID tags and readers. This substitution eliminates sensitivity to environmental factors like sunlight and humidity, as RFID uses electromagnetic fields in the radio frequency range that are not affected by these conditions. The RFID system provides reliable worker detection regardless of weather or lighting conditions.
2Productivity
If a fixed detection area is used for worker detection, then the system is simple to operate, but excessive alerts occur that reduce working efficiency
Solution Approach 1:
The patent implements dynamic detection areas that automatically adjust based on the work machine's operational state. When the machine is stationary, a smaller detection area is used. When the machine is moving or operating, the detection area expands to cover the workspace. This dynamic adjustment prevents excessive alerts during normal operations while maintaining safety, thereby improving working efficiency without requiring complex manual configuration.
Solution Approach 2:
The system continuously monitors the work machine's operational state and uses this feedback to adjust the detection area in real-time. The control unit receives signals about machine movement and operation, then modifies the detection parameters accordingly. This feedback mechanism allows the system to adapt automatically, reducing false alerts while maintaining comprehensive safety coverage.
3Loss of information
If GNSS positioning is used to obtain worker location, then positional information can be acquired, but detection reliability deteriorates due to satellite signal interference and propagation delays
Solution Approach 1:
The patent combines RFID technology with GNSS positioning to create a hybrid detection system. The RFID component provides reliable short-range detection that is not affected by satellite signal issues, while GNSS provides broader positional context. By merging these two systems, the patent overcomes the limitations of GNSS alone (signal interference, propagation delays) while maintaining the ability to provide comprehensive positional information for worker safety monitoring.
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 detects worker proximity with high accuracy, reducing excessive alerts and operational inefficiencies by combining GNSS and magnetic field induction RFID technologies to provide reliable positional information.
Implementation Method 1
a worker tag responsive to a magnetic field signal generated by the magnetic field generating device for sending a radio-wave signal
Data Source
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AI summary
An operator of a hydraulic excavator and a worker working outside of the hydraulic excavator carry a worker tag that sends a radio-wave signal including a magnetic field ID, a tag ID, and positional information obtained by a GNSS receiving section in case the worker tag receives a magnetic field signal generated by a magnetic field detecting device mounted on the hydraulic excavator. Based on positional information of the hydraulic excavator that is obtained from an GNSS receiving device and positional information of the worker tag, the position of the worker tag is calculated. In case the worker tag is detected in a proximity notification target area, a notification command is generated for notifying the operator of the hydraulic excavator of the detection of the worker tag, and output to a notification device in the cabin of the hydraulic excavator. Thus, a worker who is in proximity to the work machine is accurately detected, and the operator is prevented from being excessively alerted.