eVTOL Control Allocation for Noise and Battery Load Balancing
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Solution Overview
Problem
Electric vertical take-off and landing (eVTOL) aircraft face challenges in control allocation due to over-actuation, noise generation, and energy management, particularly in distributing control effort among multiple actuators and balancing noise and energy usage effectively.
Innovation Solution
A method and system for controlling eVTOL aircraft that involves receiving force and moment commands, solving optimization problems to minimize noise and balance energy usage by operating electric propulsion units at different speeds, tilting units, and adjusting attitudes to spread frequencies and reduce noise, while also considering battery pack energy states to optimize power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If electric propulsion units operate at the same speed to simplify control, then control system complexity is reduced, but noise amplitude increases due to concentrated frequency generation
Solution Approach 1:
The patent applies local quality by assigning different operational characteristics to different propulsion units. Specifically, it varies the speeds of individual electric propulsion units based on their local positions and noise contributions, rather than uniform operation. This allows each unit to operate optimally for its specific location, reducing overall noise amplitude while maintaining manageable control complexity through localized adjustments.
Solution Approach 2:
The patent changes operational parameters (speeds) of the electric propulsion units dynamically. By varying the rotational speeds of different propulsion units, the system spreads the generated noise frequencies across a wider spectrum, reducing peak amplitudes. This parameter variation is implemented through optimized control commands that adjust each unit's speed while maintaining overall thrust requirements.
2Use of energy by moving object
If multiple battery packs are used to increase energy capacity, then energy storage is improved, but energy balance management becomes more complex
Solution Approach 1:
The patent implements feedback mechanisms to monitor and manage the energy states of multiple battery packs. The control system continuously tracks the charge levels and performance of each battery pack, using this feedback information to dynamically adjust power distribution. This feedback loop enables automated energy balance management, reducing the complexity of coordinating multiple energy sources while maximizing overall energy utilization efficiency.
Solution Approach 2:
The control system performs self-service by autonomously managing the energy distribution among multiple battery packs without requiring external intervention. It automatically monitors energy states, identifies imbalances, and adjusts power allocation to maintain optimal energy balance across all packs, thereby simplifying the overall energy management complexity while preserving increased energy storage capacity.
3Object-generated harmful factors
If propulsion units are operated at different speeds to spread frequencies and reduce noise, then noise perception is reduced, but control allocation complexity increases
Solution Approach 1:
The patent changes the operational parameters (rotational speeds) of different propulsion units to spread noise frequencies. By varying speeds across units rather than operating them uniformly, the system distributes acoustic energy across a broader frequency spectrum, reducing perceived noise levels. This parameter variation is integrated into the control allocation algorithm to manage the increased complexity.
Solution Approach 2:
The patent introduces dynamics into the control allocation by making propulsion unit speeds variable rather than fixed or uniform. The control system dynamically adjusts each unit's speed based on real-time requirements, enabling frequency spreading for noise reduction while adapting to changing flight conditions. This dynamic approach manages control allocation complexity through adaptive rather than static control strategies.
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
A method of controlling an electric aircraft that has a plurality of actuators that includes a plurality of electric propulsion units includes: receiving force and moment commands for the electric aircraft; determining control commands for the plurality of actuators based on the desired force and moment commands by solving an optimization problem that comprises a noise minimization term for minimizing noise generated by the electric propulsion units; and controlling the plurality of actuators according to the determined control commands to meet the force and moment commands for the electric aircraft.