Asymmetric CAN Bus Redundancy for Fault-Tolerant UAS Flight Control
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Solution Overview
Problem
Existing unmanned aerial systems (UAS) lack redundancy in their controller area network (CAN) components, leading to potential system failures and reduced safety and reliability in operation.
Innovation Solution
Implementing a redundant CAN-based communication system with multiple CAN controllers and flight modules connected via multiple CAN buses, allowing components to fail without affecting the overall operation of the UAS, with asymmetric connections enabling adaptive functionality and fault tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single CAN controller and flight module are used, then the device complexity is reduced, but the reliability deteriorates due to lack of redundancy
Solution Approach 1:
The CAN system is segmented into multiple independent controllers (first CAN controller, second CAN controller) and flight modules (primary flight module, secondary flight module), each capable of independent operation. This segmentation allows the system to maintain functionality even when individual segments fail, thereby improving reliability without requiring a complete system redesign.
Solution Approach 2:
The system implements beforehand cushioning by pre-configuring redundant CAN controllers and flight modules that stand by ready to take over if the primary components fail. The asymmetric connection configuration ensures that backup components are already in place and can immediately assume control, cushioning against potential failures before they impact system operation.
2Reliability
If redundant CAN controllers and flight modules are implemented, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The system employs asymmetric connections where the first CAN controller connects to both the primary and secondary flight modules via the first CAN bus, while the second CAN controller connects to both modules via the second CAN bus. This asymmetric architecture allows for controlled redundancy where each controller has specific communication paths, managing complexity through structured asymmetry rather than complete symmetry.
Solution Approach 2:
Each CAN controller is designed with universal functionality to communicate with both flight modules through different CAN buses. The primary flight module and secondary flight module also possess universal capabilities to receive and execute commands from either controller. This multi-functionality reduces the need for dedicated point-to-point connections, thereby managing complexity while maintaining redundancy.
3Adaptability or versatility
If asymmetric connections are used between CAN controllers and flight modules, then the adaptability is improved, but the ease of operation deteriorates
Solution Approach 1:
The asymmetric CAN connection system implements dynamic adaptability where the operational configuration changes based on failure states. When a controller or flight module fails, the system dynamically reconfigures communication paths through the remaining functional components. The CAN protocol's inherent error handling and retransmission capabilities enable this dynamic adaptation without requiring manual reconfiguration, maintaining ease of operation despite the complex asymmetric topology.
Data Source
Figure 1A
Figure 1B~1C
Figure 1D
AI summary
An example embodiment includes a plurality of flight modules including a primary flight module and a secondary flight module. The embodiment includes a CAN controller, a second CAN controller, a first CAN bus configured to transmit primary control signals from the first CAN controller to the primary flight module and to the secondary flight module, and a second CAN bus configured to transmit secondary control signals from the second CAN controller to the primary flight module and the secondary flight module. The primary flight module is configured to perform functions responsive to receiving the primary control signals, and not in response to receiving the secondary control signals and the secondary flight module is configured to perform functions responsive to receiving the secondary control signals, and not in response to receiving the primary control signals.