Emergency Stop Switch Fall Detection System
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Solution Overview
Problem
Conventional emergency stop systems for machines are vulnerable to releasing the emergency stop state due to shock from dropping the emergency stop switch, especially when power is reintroduced after shutdown, potentially leading to unintended machine operation.
Innovation Solution
An emergency stop system that includes an acceleration sensor to detect falls and shocks, a control unit with fall detection, shock detection, switch state detection, and a signal output unit to maintain the emergency stop signal regardless of the switch's state after a detected fall and shock, ensuring the machine remains in a safe state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the emergency stop switch is made portable and operable by pressing, then the ease of operation is improved, but the reliability deteriorates due to shock from dropping causing unintended switch state changes
Solution Approach 1:
The acceleration sensor continuously monitors for fall conditions before the switch state can be inadvertently changed. By detecting the fall in advance and setting a flag, the system prepares to ignore subsequent switch state changes that occur during the fall period, preventing unreliable operation while maintaining ease of use
Solution Approach 2:
The system uses feedback from the acceleration sensor to dynamically control the interpretation of switch state changes. When a fall is detected, the feedback mechanism prevents the switch state change from triggering an emergency stop, thereby maintaining reliability while preserving the simple press operation capability
2Reliability
If the emergency stop state is maintained after power shutdown, then the reliability is improved, but the device complexity increases due to additional detection mechanisms
Solution Approach 1:
The acceleration sensor serves multiple functions: it detects falls during operation, detects falls during power shutdown, and provides information to the control unit to determine whether switch state changes should be honored. This multi-functionality maintains reliability across different power states without requiring separate detection mechanisms
Solution Approach 2:
The control unit uses the acceleration sensor data to automatically determine whether to respond to switch state changes, eliminating the need for separate circuitry to handle power shutdown scenarios. The system self-adjusts its behavior based on fall detection flags, maintaining reliability while avoiding additional 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
The system effectively prevents the accidental release of the emergency stop state due to shock from dropping the emergency stop switch, ensuring machine safety by maintaining the emergency stop signal even after a fall and potential power reintroduction.
Implementation Method 1
an acceleration sensor (12) that detects an acceleration of the emergency stop switch
Data Source
AI summary
An emergency stop system for suppressing the possibility that an emergency stop state of a machine is released due to the shock of the falling of an emergency stop switch that stops an operation of the machine in an emergency is provided. The emergency stop system includes: a fall detection unit that detects falling of an emergency stop switch on the basis of a detection value obtained by an acceleration sensor; a shock detection unit that detects shock after the falling of the emergency stop switch on the basis of the detection value of the acceleration sensor; a switch state detection unit that detects an ON-OFF state of the emergency stop switch; and a signal output unit that outputs an emergency stop signal to the machine regardless of the ON-OFF state of the emergency stop switch when the switch state detection unit has detected switching of the ON-OFF state of the emergency stop switch within a predetermined period after the fall detection unit detected the falling and the shock detection unit detected the shock.