Electronic Safe-Arm Device for Supercavitating Rounds
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Solution Overview
Problem
Designing an electronic safe and arm (ESAF) device for small supercavitating rounds with energetic payloads poses challenges due to space constraints and the need for multiple independent safety features, as per MIL-STD-1316F, which existing technologies struggle to meet effectively.
Innovation Solution
The ESAF device shares electronics between an unmanned underwater vehicle (UUV) and the supercavitating cargo round, utilizing onboard sensors and a distributed safety architecture with four to six independent safety features, and employs a cable mandrel with spring contacts for a reliable electrical interface that withstands high pressures and temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an ESAF device is incorporated into a small supercavitating round, then the round can carry energetic payloads, but the space constraints make it problematic to fit the ESAF device and supporting electronics on board
Solution Approach 1:
The system is divided into two segments: the UUV platform and the cargo round. The ESAF electronics are distributed between these segments, with sensors and control electronics located on the UUV and the fuze mechanism in the cargo round. This segmentation allows the small round to carry energetic payloads without requiring all safety electronics to be contained within its limited volume.
Solution Approach 2:
The UUV platform serves multiple functions: it acts as the weapons platform, hosts the ESAF sensors, provides control electronics, and serves as the launch system. By making the UUV multi-functional, the system eliminates the need to miniaturize sensors for the small cargo round while still achieving safe and arm functionality.
2Reliability
If multiple independent safety features are implemented to meet MIL-STD-1316F, then the probability of unintentional arming is reduced, but the device complexity increases
Solution Approach 1:
Multiple independent safety features are merged into a distributed architecture where sensors, control logic, and fuze mechanisms work together across the UUV-platform and cargo-round boundary. This integration achieves the required safety redundancy without concentrating all complex components in one location, thereby managing overall system complexity.
Solution Approach 2:
The control system acts as an intermediary between the sensors on the UUV and the fuze mechanism in the cargo round. It processes sensor inputs, executes safety logic, and controls the fuze timing, thereby coordinating multiple independent safety features while managing system complexity through centralized control logic.
3Measurement precision
If sensors are installed in the small cargo round, then arming conditions can be sensed, but there isn't room for that many sensors and some cannot be miniaturized
Solution Approach 1:
The sensing function is extracted from the cargo round and relocated to the UUV platform. Sensors for detecting arming conditions (such as depth, pressure, and environmental parameters) are installed on the larger UUV where space is available, eliminating the need to miniaturize sensors or compromise the small volume of the cargo round.
Data Source
AI summary
An article comprising an electronic safe-arm and fire (ESAF) device for a supercavitating cargo round (SCR) includes discrete electronics, a high-voltage capacitor, a high-voltage switch, and an exploding foil initiator. The discrete electronics includes digital-delay timer circuits, discrete logic circuits, accelerometers, and circuitry for enabling the high-voltage switch. In a method for implementing the safe and arm protocols, sensor readings from sensors on a weaponized UUV are obtained and, when certain conditions are achieved, remove inhibit signals are forwarded to a controller onboard the UUV. When such signals are received in a specified order, and within certain optional specified time delays, the controller arms the ESAF within the SCR. After the SCR fire and leaves the barrel on the UUV, the ESAF monitors certain acceleration/deceleration conditions unique to supercavitation, and applies same to determine whether to detonate the SCR's energetic payload.