# Advancing Road Infrastructure Safety with the Remotely Piloted Safety Cone
## 2 Materials and Methods
### Hardware Architecture  
The RPSC integrates COTS hardware to minimise development time and ensure reliability, as detailed in Table 4. The components were selected to meet the design requirements and comply with the UNE-EN 13422:2019 and UNECE standards. The RPSC's robotic platform was built upon the GoBilda Recon chassis, a commercial solution that offers dimensional compatibility with the base of standardised traffic cones used in Europe under the UNE-EN 13422:2019 regulation. This structure provides a stable foundation and enables the direct mechanical integration of propulsion modules, sensors, and power systems without compromising the device's stability. This choice significantly reduces the need for custom parts, simplifies assembly logistics, and ensures component interoperability, with all elements sourced from a single supplier. Figure 3 shows the assembled RPSC, which integrates the propulsion modules, sensors, and GNSS module on the GoBilda Recon chassis, highlighting the compact design that allows for combining a regulatory safety cone. Figure 3a shows the RPSC's electronic module, where the Pixhawk, Driver, and Raspberry Pi are mounted on a 3D-printed structure. Figure 3b shows the RPSC, with all the propulsion and sensing modules integrated; the GNSS receiver is located at the top to avoid electromagnetic interference and ensure optimal satellite signal reception. Figure 3c shows the RPSC in its final configuration, ready to be deployed in road maintenance works, incorporating a homological signalling cone on the robotic platform to ensure compliance with current regulations. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Component** & **Function** & **Subsystem** & **Specifications** & **Justification** \\ \hline GoBilda Recon Chassis [1] & Structural support & Platform & Height: 750 mm, base: 400 mm, weight: 4 kg & Compliant with UNE-EN 13422:2019, modular design \\ \hline GoBilda Yellow Jacket & Traction motors with encoders & Propulsion & 12 V, 300 RPM, Hall-effect encoders & Balanced speed/torque, supports odometry \\ \hline GoBilda All-Terrain & Traction on varied & Propulsion & Diameter: 140 mm, foam inserts & High grip, suitable for asphalt and gravel \\ Wheels [1] & surfaces & & & and gravel \\ \hline Pixhawk 2.4.8 [2] & Navigation and state estimation & Autopilot & 6-axis IMU, 32-bit ARM Cortex-M4 & Open-source, multi-sensor support \\ \hline Here3+ GNSS [3] & RTK positioning & Navigation & GPS/GLONASS/Gaillee/BeiDou & \textless{}10 cm accuracy with RTK \\ \hline HC-SR04 Ultrasonic Sensor [4] & Obstacle detection & Sense and Avoid & Range: 4 m, beam angle: 15\({}^{\circ}\) & Cost-effective, reliable in varied conditions \\ \hline Raspberry Pi 5 [5] & High-level processing and communication & OPU & Quad-core Cortex-A76, 8 GB RAM & ROS2 compatible, high computational capacity \\ \hline Alfa AWUS036 ACH Wi-Fi & Wireless & Communication & Dual band (2.4/5 GHz), range: 100 m & Long-range, low-latency \\ \hline Zeee 9500 mAh DiPo 3 SIP & Power supply & Power System & 11.1 V, 9500 mAh, 3 SIP & High capacity, lightweight \\ Battery [7] & & & configuration & \\ \hline Holybro PM07 [8] & Voltage regulation for Pixhawk & Power System & 5.1 V output, current monitoring & Stable power supply, battery health monitoring \\ \hline UBEC 5 V [9] & Voltage regulation for Raspberry Pi & Power System & 5 V output, max current: 3 A & Efficient conversion, compact design \\ \hline \hline \end{tabular}  
* Manufacturer: goBilda, Greenville, TX, USA, [2] Manufacturer: Holybro, Shenzhen, China, [3] Manufacturer: CubePlot, Taipei, Taiwan, [4] Manufacturer: Electrow, Shenzhen, China, [5] Manufacturer: Raspberry Pi Ltd., Cambridge, UK, [6] Manufacturer: Alfa Network, Taipei, Taiwan, [7] Manufacturer: Zeee Power, Dongguan, China, [8] Manufacturer: Holybro, Shenzhen, China, [9] Manufacturer: Hobbywing, Shenzhen, China.  
\end{table} 
Table 4: RPSC hardware components.