Fire and rescue operations often involve navigating through smoke-filled, high-temperature, impact-prone, and communication-dead zones. These environments are hazardous to human responders, especially during reconnaissance missions in structurally unstable or fire-damaged buildings.
Abhishek Malhotra
May 24, 2025
The Ornsköldsvik Fire Department wanted to integrate the Unitree Go2 Air robot dog into their rescue workflow. While the robot provides excellent mobility and agility, it is not inherently designed for extreme conditions like direct flame exposure, falling debris, or wireless blackout areas.
The core challenge was to design a rugged electronics system that could allow the Unitree Go2 Air to operate reliably in fire-prone, debris-heavy, and disconnected environments, while preserving its natural balance and agility.
Objectives
Protect sensitive electronics from fire, shock, and impact.
Enable cellular (4G/5G) communication to eliminate dependency on Wi-Fi.
Design a rugged, securely mounted backpack that does not affect the Go2 Air’s mobility.
Maintain field serviceability for quick hardware swaps or updates.
Engineering Solution
1. Enclosure and Mounting Design
Backpack Frame:
Custom-designed using aerospace-grade aluminum (6061-T6), lightweight yet strong.
Secured using Kevlar-reinforced tension straps aligned with the Go2 Air’s center of gravity.Enclosure Design:
Built with a dual-layer architecture:Outer shell: Anodized aluminum for thermal shielding and impact resistance
Inner shield: Aerogel-insulated liner for up to 500°C short-term protection
IP65-rated rubberized gaskets to seal off smoke, water splashes, and dust
2. Electronics System Integration
Compute Core:
Raspberry Pi 5 with conformal coating for added thermal and shock protection.
Passive heat sink and internal thermal spreader for heat control.Connectivity:
4G-enabled Android device mounted inside the enclosure, set to hotspot and data relay mode.
BLE module for low-range fallback communication.
Configurable auto-switching mechanism between Wi-Fi and 4G.Power System:
Independent LiFePO₄ battery module, selected for thermal stability and safety.
USB-C PD circuit for emergency power delivery to the onboard system.
Environmental & Impact Testing
Thermal Exposure:
Tested in a fire-simulated chamber at 300°C ambient for 6 minutes. Electronics remained operational.Shock and Drop Test:
Survived drops from 1.8 meters onto hard surfaces.
Simulated debris collision using a swinging-arm impactor (10kg at 1 meter).Connectivity Test:
Maintained live telemetry and command relay in a Wi-Fi-dead fire drill zone, purely over 4G.
Results & Deployment
The first prototype was deployed in controlled fire rescue simulations involving collapsed structures, thick smoke, and thermal hotspots. The Unitree Go2 Air with the rugged backpack successfully performed visual reconnaissance, audio relay, and command response in real-time.
Key Outcomes
100% electronics uptime in harsh test environments
Zero communication dropouts during 4G fallback trials
Fully field-serviceable design, with tool-less access to internal hardware
Maintained full agility and response of the robot under added payload conditions
