Accelerometer-Based Impact Detection for Automatic Closure Systems
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Solution Overview
Problem
Automated closure systems, such as garage doors and windows, lack mechanisms to prevent damage or injury from closing onto objects or people, as existing sensors like optical sensors are often ineffective in detecting obstructions, especially at varying heights or in different types of closure systems.
Innovation Solution
A system comprising an accelerometer, comparator circuits, and a microcontroller that detects the motion and impact of a closure system, with adjustable sensitivity and communication to a remote controller for triggering alarms or controlling the motor, allowing for automatic termination of the closure action upon impact detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical sensors are used to detect obstructions, then detection capability is improved at ground level, but detection reliability deteriorates for obstructions at varying heights or in different closure system types
Solution Approach 1:
The patent replaces optical sensors with a mechanical impact detection system using an accelerometer mounted on the closure. The accelerometer detects physical impacts through acceleration forces, providing reliable detection across all obstruction heights and closure system types without relying on line-of-sight optical paths.
Solution Approach 2:
The patent changes the detection parameter from optical presence (optical sensors detecting light blockage) to mechanical impact (accelerometer detecting acceleration forces). This parameter change enables universal application across different closure systems and obstruction types, as mechanical impact is detectable regardless of obstruction height or material properties.
2Device complexity
If no impact detection mechanism is provided, then device complexity is reduced, but harmful effects increase due to potential damage and injury from uncontrolled closure
Solution Approach 1:
The closure system performs self-diagnosis through the accelerometer mounted on the closure itself. The closure detects its own impact conditions and autonomously triggers the control signal to reverse or stop closure, eliminating the need for external monitoring systems or complex safety infrastructure.
Solution Approach 2:
The patent implements a feedback loop where the accelerometer continuously monitors closure motion, the microcontroller analyzes acceleration data to detect impacts, and the system responds by sending control signals to reverse or stop closure. This closed-loop feedback provides reliable harm prevention with minimal added complexity.
3Measurement precision
If sensitivity is increased to detect all impacts, then detection capability is improved, but false detection increases due to normal operation vibrations
Solution Approach 1:
The patent employs dynamic threshold adjustment where the microcontroller learns normal operational vibration patterns during idle periods and adapts the impact detection threshold accordingly. The system distinguishes between normal vibrations (during opening/closing) and abnormal impacts by comparing acceleration patterns against learned baselines, reducing false detections while maintaining sensitivity.
Solution Approach 2:
The system performs preliminary learning of normal operational characteristics during idle periods before impact detection is activated. The microcontroller stores baseline vibration patterns and uses this preliminary data to differentiate between normal operation and actual impacts, enabling accurate detection without false alarms.
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
Effectively prevents damage and injury by automatically detecting impacts and terminating the closure action, enhancing safety in various automated closure systems beyond the limitations of existing sensors.
Implementation Method 1
providing an accelerometer responsive to motion of a closure forming part of an automatic closure system
Implementation Method 2
providing an output of the accelerometer to first and second comparator circuits, the first comparator circuit having a first reference voltage such that the output of the first comparator circuit is indicative of a direction of motion of the closure
Data Source
AI summary
A method is provided, including providing an accelerometer responsive to motion of a closure forming part of an automatic closure system, providing an output of the accelerometer to first and second comparator circuits, the first comparator circuit having a first reference voltage such that the output of the first comparator circuit is indicative of a direction of closure motion and the second comparator circuit having an adjustable second reference voltage such that the output of the second comparator circuit is scaled relative to this adjustable second reference voltage to adjust the sensitivity of the output of the second comparator, providing a microcontroller coupled to the first and second comparator circuits, the microcontroller determining both a motion sequence of the closure and whether the closure has impacted an object, and providing an interface circuit for communicating the output from the microcontroller to a remote controller circuit.