Design and Control of Power Transmission System for Dual-Engine Variable-Pitch Multirotor UAV

AbstractThis manuscript, Design and Control of Power Transmission System for Dual-Engine Variable-Pitch Multirotor UAV, presents a fully integrated dual-engine variable-pitch power transmission architecture with real-time fault detection and rapid reconfiguration. The design uses a modular belt-gear coupling and a supervisory control algorithm to allocate torque and redistribute power following faults. Experimental ground and flight tests demonstrate fault detection and correction within 85 ms, thrust error below 4.3%, attitude variation within ±2.8°, and fault-tolerant flight endurance beyond 15 minutes in emergency scenarios. The architecture combines mechanical redundancy, high-precision gearing (DIN Class 6), composite-wrapped drive shafts, and an adaptive control strategy to improve reliability and mission survivability compared with conventional single-engine multirotor designs. MethodsThe study combines CAD/FEA structural design, modular gearbox prototype bench tests, and MATLAB/Simulink control simulations. A multi-sensor fusion approach (IMU, torque sensors, vibration and temperature monitoring) is used for state estimation and Kalman-filter-based fault detection. Control logic integrates PID, fuzzy techniques, and model-predictive elements to synchronise dual-engine outputs and coordinate variable-pitch actuation. Performance metrics were assessed via static bench tests and flight trials on a hexacopter platform with a 500 Hz sampling loop. Key contributions A novel redundant mechanical power transmission architecture for dual-engine multirotor UAVs. Detailed design and FEA validation of a modular gearbox and composite drive shaft. A supervisory control algorithm enabling power reallocation and variable-pitch coordination with sub-100 ms switching. Prototype test and flight validation demonstrating improved fault tolerance, thrust precision, and attitude stability. Results & performanceBench and flight tests report transmission efficiency ≥92.5%, pitch response ≈38 ms, thrust adjustment error ≈4.3%, attitude control error within ±2.8°, and fault compensation completed in ~85–100 ms across fault scenarios. Fault-scenario tables and parametric analyses are included in the full text.