Electronic Setback Detection for 40 mm Munitions
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Solution Overview
Problem
Current mechanical setback detectors in gun launch environments suffer from latency issues due to battery activation time, unreliable detection of setback forces, and inability to differentiate between setback and false drop conditions, particularly during the early phase of launch when the battery is not activated.
Innovation Solution
An all-electronic setback force detection system using a piezoelectric transducer and electronic components to convert and store vibrational energy onto a storage capacitor, allowing for real-time sensing of setback forces without relying on battery power, thereby eliminating timing errors and improving accuracy by sensing both frequency and force responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical setback detectors are used, then the structure is simple and easy to manufacture, but the detection reliability is poor and timing errors occur due to battery latency
Solution Approach 1:
The patent replaces the mechanical setback detector with an electronic system comprising a piezoelectric transducer, amplifier, and capacitor. The piezoelectric transducer converts mechanical setback forces directly into electrical signals, which are then amplified and stored on a capacitor for detection. This substitution eliminates the need for batteries and mechanical moving parts, thereby improving reliability while managing complexity through solid-state electronics.
Solution Approach 2:
The electronic setback detection system is designed to be self-powered during the critical early phase. The piezoelectric transducer generates electrical energy directly from the setback force, which is then stored on a capacitor to power the detection circuitry. This self-service mechanism eliminates dependency on external battery power during the initial detection period, improving reliability without requiring complex power management systems.
2Speed
If mechanical setback detectors are used, then the device complexity is low, but the response time is slow due to battery activation latency
Solution Approach 1:
The system performs preliminary action by having the piezoelectric transducer immediately convert setback forces into electrical signals at the moment of impact, without waiting for battery activation. The generated electrical energy is stored on a capacitor in real-time, allowing the detection circuit to operate immediately when power becomes available. This preliminary conversion and storage of energy eliminates the latency associated with battery activation, achieving fast response times while using manageable electronic components.
3Measurement precision
If mechanical setback detectors are used, then the manufacturing is simple, but the ability to differentiate setback from false drop conditions is poor
Solution Approach 1:
The electronic detection system incorporates feedback mechanisms through the amplifier and capacitor configuration. The system monitors the electrical signals generated by the piezoelectric transducer, amplifies them to detectable levels, and stores them on a capacitor for analysis. This feedback loop allows the system to distinguish between genuine setback forces (which generate specific signal patterns) and false drop conditions (which produce different signal characteristics), thereby improving measurement precision while using standard electronic manufacturing processes.
Solution Approach 2:
The patent utilizes parameter changes in the electrical domain to improve detection accuracy. The piezoelectric transducer converts mechanical forces into electrical signals with specific voltage and frequency characteristics. By amplifying and storing these signals on a capacitor, the system can analyze parameters such as signal amplitude, duration, and pattern to differentiate between legitimate setback events and false drop conditions. This parameter-based differentiation achieves high measurement precision using conventional electronic manufacturing techniques.
4Measurement precision
If electronic components with battery are used, then the detection accuracy is improved, but the power consumption increases and battery latency occurs
Solution Approach 1:
The system implements self-service by using the piezoelectric transducer to generate electrical energy directly from the setback force. This generated energy is stored on a capacitor, providing power to the detection circuitry without requiring an external battery. The capacitor maintains the electrical charge long enough for the detection system to operate and record the setback event. This approach achieves high detection accuracy while minimizing power consumption, as the system is powered solely by the energy from the setback event itself during the critical detection period.
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 provides faster and more reliable detection of setback forces, enabling accurate arming of fuze circuitry, reducing mechanical complexity, and enhancing the ability to distinguish between real launch and false drop conditions, with improved versatility for sensing low and high acceleration munition rounds.
Implementation Method 1
striking a piezoelectric transducer with a mass, and filtering that generated electrical energy of the setback environment
Implementation Method 2
storing electrical energy generated from a setback environment onto a storage capacitor in real time
Data Source
AI summary
In a projectile launch environment, a fuzing safety device independently generates its own voltage upon setback which then is then used to arm the projectile. The arming is done independently of any on board battery rise time, and setback scenarios are detected free of false impacts such as dropping or jostling. The fuzing safety device includes a piezoelectric sensor for detecting motion in the projectile.