RFID Operator Separation Detection for NC Machine Tools
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Solution Overview
Problem
In access-level control apparatuses for NC machine tools, determining appropriate timing for operator separation and accurately limiting authentication areas using RFID authentication is challenging, leading to potential unauthorized operations and information leaks.
Innovation Solution
An access-level control apparatus that includes an RFID held by operators, a reader unit with a transmission antenna radiating a near magnetic field for re-authentication, and a separation detecting unit that determines operator separation based on signal reception intensity changes, allowing for timely authentication release and accurate area limitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RFID authentication is used to limit operator access in NC machine tools, then operator security and information protection are improved, but accurate determination of operator separation timing and authentication area limitation deteriorate
Solution Approach 1:
The patent introduces a separation detecting unit as an intermediary component that uses RFID signal reception intensity as a mediator to indirectly detect operator separation. Instead of directly detecting separation, the system measures the RFID signal strength, which naturally decreases with distance, and uses this intermediate measurement to determine when the operator has left the authentication area, thereby achieving accurate separation detection while maintaining security.
2Reliability
If RFID authentication area is expanded to ensure operator detection, then operator authentication reliability is improved, but authentication area limitation to appropriate range (1m-2m) deteriorates
Solution Approach 1:
The patent applies dynamics by making the authentication area effectively dynamic through signal intensity threshold adjustment. Instead of using a fixed physical boundary, the system dynamically determines the authentication area based on RFID signal reception intensity thresholds, allowing the effective authentication zone to adapt to different operating conditions while maintaining the appropriate 1m-2m range limitation.
Solution Approach 2:
The system changes the parameter of signal reception intensity threshold to control the authentication area boundary. By adjusting this parameter, the system can precisely limit the authentication area to the appropriate 1m-2m range from the display unit while maintaining reliable authentication, as the threshold determines when signal strength indicates operator presence or absence.
3Difficulty of detecting and measuring
If RFID signal reception is used for continuous monitoring, then separation detection capability is improved, but system complexity and false detection risk worsen
Solution Approach 1:
The RFID system performs self-service by using its own signal reception intensity characteristics for separation detection. The same RFID infrastructure used for authentication automatically provides separation detection information through signal strength measurement, eliminating the need for separate sensors or complex monitoring equipment, thus improving detection capability while minimizing added system complexity.
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
This solution enables stable and secure authentication of operators, reducing the risk of unauthorized operations and information leaks by accurately detecting operator separation and limiting authentication areas, even in noisy environments.
Implementation Method 1
the reader unit includes a transmission antenna that radiates a calling signal with a near magnetic filed as a signal for calling the RFID
Implementation Method 2
the RFID responses to the reader unit and if the signal received form the reader unit is not the normal call signal, then the RFID does not response to the reader unit
Data Source
AI summary
An access-level control apparatus includes an NC machine tool, an RFID that is held by an operator and stores an ID given to the operator, a reader unit that reads out the ID, an authenticating unit that determines operator processing limitation information including an operable range by the operator associated with the ID or display information provided to the operator, an operation/display limiting unit that limits processing by the operator for the NC machine tool on the basis of the operator processing limitation information, and a separation detecting unit that periodically reads out, after the authentication, the ID in the RFID, performs re-authentication, and detects presence or absence of separation of the operator. When detecting as a result of the re-authentication that the operator separates from the NC machine tool, the separation detecting unit releases the authentication.