FlyCore Structural Installation Guide

Scope: Structural installation, vibration isolation, thermal design, and electrical connection requirements for the flight control computer (FlyCore-FC), onboard edge computing unit (FlyCore-U), LiDAR (LiDAR/MID360), and visual perception cameras (stereo/monocular/TOF).

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Part 1: System Overview and Core Design Principles

Purpose and How to Read This Guide

Purpose
This guide standardizes the mechanical installation interfaces for high-precision sensors and computing units to ensure consistent and repeatable flight controller attitude estimation, onboard computing data processing, and sensor perception. In addition to assembly procedures, it specifies the interface and acceptance requirements that third-party complete-system teams must follow during integration.

Intended Audience and Conflict Resolution
This document is intended for mechanical and electrical engineers and third-party complete-system integrators. English abbreviations or technical terms used in this document are generally explained upon first use; see the appendix at the end of this document for the complete glossary.
If the requirements in this document conflict with the manual for your own platform, the official interface documents and airworthiness/safety requirements issued by the payload manufacturer shall prevail.

Payload List and Functional Roles

After receiving or unpacking the shipment, first check the following three types of kits against the shipping BOM. Do not install the equipment if any item is missing or incorrect.

The functional roles of the components are as follows:

• FlyCore-FC (flight controller board): The bottom board and the core platform for flight control functions. It incorporates an IMU (inertial measurement unit, used for attitude measurement), RTK, broadcast module, and other components, and is responsible for attitude control and navigation. The onboard IMU is the reference for complete-system attitude estimation.
• FlyCore-U (onboard computer): A high-performance computing center that serves as the "brain" for fusion localization and perception algorithms. It runs algorithms such as data fusion, AI recognition, and SLAM (simultaneous localization and mapping).
• MID360 (LiDAR): Outputs 3D point cloud data for obstacle avoidance, surveying and mapping, and vision-LiDAR fusion localization.
• Front/rear cameras (stereo/monocular vision): Connect to FlyCore-U through MIPI interfaces and support visual localization, target recognition, and ranging.
• Adapter board: Expands the external interfaces of FlyCore-U, such as Ethernet, LiDAR power, and serial ports.
• Brackets, standoffs, and base: Structural components used for load bearing, positioning, and interlayer connections.

Four Core Design Principles

Combining Rigidity and Flexibility (Co-Mounting LiDAR and Vision Sensors)

• Rigid co-mounting (mandatory): The front camera (vision) and MID360 (LiDAR) must be rigidly mounted on the same primary structural component (such as the same sensor bracket). Their relative pose must be maintained by that structural component. No vibration-isolation balls, soft rubber pads, or other vibration isolators may be installed in series between them. This is a mandatory prerequisite for ensuring that the "LiDAR-vision extrinsic parameters" remain consistent under vibration and temperature changes.
• Independent vibration isolation: FlyCore-FC (flight controller) must be separated from the rigid sensor bracket described above and use its own vibration isolation to suppress the effect of high-frequency vibration on the IMU.

Thermal Management

• For the high-power FlyCore-U, priority must be given to the quality of the thermal interface material (TIM), and an unobstructed, stable cooling airflow path must be provided.
• Low-power vision components require protection against dust and condensation and must not be exposed directly to hot exhaust air.

Sensor Field-of-View and Overlap

• Field-of-view protection: The camera FOV (field of view) and the LiDAR scanning plane must not be obstructed by the aircraft structure, wiring harnesses, or other components.
• LiDAR-vision overlap: The LiDAR scanning range and the visual FOV should overlap as much as possible in the primary perception direction for the mission. The larger the overlap, the better the fusion localization and obstacle avoidance performance. A diagram of the overlapping region must be produced during the design phase.

Vibration Isolation

• Independent vibration isolation (mandatory): FlyCore-U (onboard computer) and FlyCore-FC (flight controller) must use independent vibration-isolation designs. Never mount both boards on the same vibration-isolation plate, as vibration generated by the onboard computer could be transmitted to the flight controller and affect attitude estimation accuracy.

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Part 2: Detailed Installation Specifications and Requirements

FlyCore-FC Installation Specifications

Installation Location

• Plan the installation location using the onboard IMU as the spatial reference, rather than the PCB outline.
• Preferably locate the IMU near the complete system's center of gravity or in an area with high structural rigidity. Do not install it on a thin-walled panel or a long cantilever.

Vibration-Isolation Platform Design

• Select vibration isolators based on the complete system's measured vibration spectrum, not on experience alone.
• The vibration isolators must be arranged symmetrically, and the horizontal projection of the onboard IMU reference point must lie within the vibration-isolation support polygon.
• Mechanical travel stops must be provided to prevent the vibration-isolation system from exceeding its travel and colliding under high overload.

Installation Orientation and Coordinate System

• Attitude reference: The flight controller installation orientation must be based on the body-axis definition of the onboard IMU (see the flight controller manual or silkscreen markings).
• Drawing requirements: Clearly mark the correspondence between the "aircraft body axes ↔ flight controller IMU axes" and the installation angle tolerances on the drawing. Do not determine the orientation visually using only the PCB outline or enclosure markings.

FlyCore-U Installation Specifications

Structural Load Bearing

• Use a CNC-machined aluminum-alloy heat-dissipation base to provide both strength and thermal conduction. The third-party mounting surface must be accompanied by evidence of flatness.

Thermal Interface Material (TIM)

• A low-hardness thermal pad with a compression ratio of approximately 30%, or thermal grease, is recommended.
• Acceptance criterion: After installation, disassemble and inspect the assembly. The TIM compression imprint must be continuous and complete, indicating good contact.

Airflow Design

• Define the intake and exhaust paths clearly, and prevent hot exhaust air from recirculating into the camera area.
• Wiring harnesses must not be routed tightly against the base of the heat sink fins, to prevent localized heat buildup.

LiDAR (MID360) and Vision Camera Installation Specifications

Rigid Connection (Co-Mounting LiDAR and Vision Sensors)

• The MID360 must not be mounted through any vibration-isolation device and must be rigidly secured directly to the primary load-bearing structure of the airframe.
• The front camera and MID360 must be rigidly secured to the same primary structural component. After installation, hold and shake this structural component to verify that there is no relative looseness between the LiDAR and camera mounts.

Field-of-View and Overlap Protection

• Ensure that the aircraft arms, landing gear, wiring harnesses, and other components do not enter the LiDAR scanning field of view. If complete avoidance is not possible, identify the obstructions in an obstruction assessment diagram.
• Adjust the layout so that the LiDAR scanning range and the visual FOV overlap as much as possible, preventing them from "looking in separate directions."
• The third party must submit an obstruction assessment diagram (including a diagram of the LiDAR-vision overlap region).

Fixed Stereo Baseline

• The stereo baseline (distance between the left and right optical centers) and optical-axis parallelism must remain stable. After calibration, never change the relative positions of the camera mounts.

Connection Between the Cameras and FlyCore-U

• Structure: The camera mount is installed on the primary structural component that carries the LiDAR and connects to FlyCore-U through a MIPI link.
• Wiring harness: The MIPI cable length and bend radius must comply with the manual. The connectors must be fully inserted and locked, and a stress-relief bend must be provided in the wiring harness to prevent it from pulling on the connector.

Optical Filter and Field-of-View Obstruction

• Light transmittance must be >90%. The filter must have an anti-reflective coating and a water- and stain-resistant coating.
• The camera front-window opening must be larger than the projection of the camera's maximum FOV. If constrained by the structure, record the acceptable obstruction range.

Electrical Interface and Cable Interconnection Specifications

High-Speed Cables (Coaxial/MIPI)

• Bend radius: The minimum bend radius of a coaxial cable must be > 5 times the cable diameter. Sharp bends are prohibited.
• Securing and protection: MIPI links must strictly follow the routing rules. Confirm a second time that connectors are locked, and provide stress relief at bends. For outdoor applications, additional dust and moisture protection must be provided.

Connector Loosening Prevention

• Critical connectors must use locking types.
• UV adhesive/silicone may be applied for securing, but it must not contaminate the terminal area.

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Part 3: Quick Assembly Guide (Assemble According to the Diagrams)

Perform the layered assembly by referring to the "Simplified Installation Example Diagram" at the beginning of this document. It is recommended to perform the corresponding inspection immediately after completing each layer.

Assembly Layer Overview (Bottom to Top)

Base → FlyCore-FC → Standoffs (M3×35) → FlyCore-U → Adapter Board/Cables → Top Bracket (MID360 + Front Camera)

Detailed Steps and Concurrent Inspections

1. Install the bottom layer (base + FlyCore-FC)

   • Assembly: Secure FlyCore-FC to the base on a flat mounting surface. Tighten the screws diagonally.
   • Concurrent inspection: Before tightening, verify the correspondence between the IMU X/Y/Z axes and the aircraft orientation according to "§4.3 Installation Orientation." If vibration-isolating mounting is used, arrange the wiring harnesses properly to prevent them from later restricting the travel of the vibration-isolation system.

2. Build the middle layer (standoffs + FlyCore-U)

   • Assembly: Install the M3×35 standoffs and tighten them diagonally in two passes. Then secure FlyCore-U to the tops of the standoffs.
   • Concurrent inspection: Check whether the compression imprint of the TIM (thermal pad/thermal grease) between FlyCore-U and the heat sink is continuous and complete. Confirm that the airflow direction is correct.

3. Routing and interface connections (adapter board & cables)

   • Assembly: Connect FlyCore-U to the adapter board, ensuring that all connectors are fully mated. Plan the routing directions for the Ethernet, LiDAR power, serial port, and other wiring harnesses.
   • Concurrent inspection: Confirm that all latches/fasteners are in place. Provide stress relief in the wiring harnesses; they must not restrict vibration-isolated or moving parts.

4. Assemble the top sensors (bracket + MID360 + front camera)

   • Assembly: Work at a clean workstation. Install the MID360 and front camera on the same top bracket. Keep the LiDAR scanning plane horizontal and the stereo cameras' optical axes aligned at the same height.
   • Concurrent inspection: Gently shake the complete bracket assembly and verify that there is no relative displacement between the camera and LiDAR mounts. Check that the optical paths are unobstructed, and secure the focus rings with adhesive as required by the process.

5. Join the top layer to the complete system

   • Assembly: Secure the top bracket assembly with the sensors to the FlyCore-U structure below.
   • Concurrent inspection: Gently shake the complete system and verify that there is no looseness or abnormal noise.

6. Final inspection before power-on

   • Remove the camera protective caps and confirm that the windows are clean and free of contamination.
   • Confirm again that the FlyCore-FC IMU vibration-isolation mount can move slightly and is not restricted by the wiring harnesses.
   • Recheck the rigidity of the LiDAR-vision co-mounting and the locked state of the MIPI connectors.

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Part 4: Integrated Testing and Acceptance Criteria

After powering on the complete system, perform the following integrated tests as needed to verify installation quality.

Quick Third-Party Acceptance Checklist

• Before installation: Mechanical interfaces, power/data links, synchronization interfaces (PPS/GPS hardware synchronization), and environmental limits (vibration/thermal/EMI) have been confirmed.
• During installation: Mandatory items such as rigid LiDAR-vision co-mounting, optical-axis alignment at the same height, complete TIM contact, connector locking, and freedom of movement for flight controller vibration isolation have been completed.
• After integrated testing: Records such as the torque sheet, interface register, calibration parameters, and test logs are complete and archived.

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Part 5: Appendix

Brief Definitions of Terms and Abbreviations

• IMU: Inertial measurement unit, a sensor used to measure an object's three-axis attitude angles and acceleration.
• TIM: Thermal interface material, which fills the gap between a heat-generating chip and a heat sink to improve heat transfer efficiency.
• MIPI: Mobile Industry Processor Interface; here, it refers to an interface standard used for high-speed data transmission between cameras and processors.
• PPS: Pulse-per-second signal, used to achieve high-precision time synchronization between devices.
• FOV: Field of view, the angular range observable by a camera or sensor.
• SLAM: Simultaneous localization and mapping, a technology for simultaneously determining a system's own position and building a map of an unknown environment.

Quick Reference for Targeted Design Recommendations

• For LiDAR: Use rigid mounting, align its forward orientation with the vision sensors, and maximize field-of-view overlap. After installation, prioritize verification of static point cloud noise and dynamic ghosting.
• For vision cameras: Install them on the same primary structural component as the LiDAR, with particular attention to camera micromovement and MIPI wiring-harness stress. Do not adjust their relative positions after calibration.
• For the onboard computer and flight controller: Maintain independent vibration isolation and independent power supplies to reduce the risk of electrical and vibration coupling.

Three Non-Negotiable Rules

1. LiDAR-vision co-mounting: The front camera and MID360 must be mounted on the same primary structural component, with no vibration-isolation pad between them.
2. LiDAR-vision alignment: The LiDAR scanning range and camera field of view should overlap as much as possible to support fusion localization.
3. Use the IMU as the attitude reference: The axes of the IMU on the flight controller board are the reference for attitude estimation; the structural installation and parameter configuration must be aligned with them.