Experimental System Design of a Fault-Tolerant Quadrotor for Rapid Rotation and Rotor Failures

Belangrijkste concepten

This paper presents an algorithmic and mechanical approach to addressing the quadrotor fault-tolerant problem in case of rotor failures, including a fault-tolerant detection and control scheme, and a modular mechanical design to enhance the steady-state angular velocity dynamics for flight safety.

Samenvatting

The paper introduces and validates a fault-tolerant control scheme that combines multiple attitude error metrics with a fault-tolerant detection module. It studies the intricate connection between the introduction of augmented drag obtained through a modular mechanical design appendage and the resulting yaw rate of the compromised quadrotor, aiming to enhance steady-state angular velocity dynamics for flight safety.

The key highlights and insights are:

1. The paper evaluates three distinct reduced attitude error metrics (current yaw, S2, and thrust vector) for fault-tolerant control, finding the S2 and thrust vector methods perform similarly and better than the current yaw metric.
2. The fault detection algorithm uses L1 adaptation to estimate the damage percentage of each rotor-propeller pair, triggering the transition to fault-tolerant control when damage exceeds 50%.
3. Experiments show the maximum speed of the fault-tolerant controller is 3 m/s and the maximum attitude angle (roll, pitch) is approximately 30°. Aggressive maneuvers result in large position errors.
4. The paper analyzes the relationship between the added rotational drag and the resulting steady-state yaw rate, providing a platform-agnostic guideline that the drag coefficient should be between 0.05 to 0.35 to maintain a controllable yaw rate within the gyroscope limits.
5. The transition from normal to fault-tolerant control requires a reaction time of 100-150 ms and sufficient initial altitude (at least 1 m) to avoid a dramatic descent during the transition period.

Statistieken

The quadrotor used in the experiments has a total weight of 700 g and a thrust-to-weight ratio of 2.5 to 1.
The gyroscope on the platform is rated up to 35 rad/sec (±2000°/s).

Citaten

"Quadrotors have gained popularity over the last decade, aiding humans in complex tasks such as search and rescue, mapping and exploration. Despite their mechanical simplicity and versatility compared to other types of aerial vehicles, they remain vulnerable to rotor failures."
"We find the maximum speed of our fault-tolerant controller to be 3 m/s and the maximum attitude angle (roll, pitch) to be approximately 30°. The maximum speed is due to the current size of our indoor arena, and the system is capable of greater speeds with the room for further acceleration."
"To maintain a controllable steady-state yaw rate, the quadrotor's rotational drag coefficient should fall within the range of 0.05 to 0.35, irrespective of the platform."

Belangrijkste Inzichten Gedestilleerd Uit

Experimental System Design of an Active Fault-Tolerant Quadrotor

by Jennifer Yeo... om arxiv.org 04-10-2024

https://arxiv.org/pdf/2404.06340.pdf

Diepere vragen

How could the fault detection and transition time be further improved to minimize altitude loss during the transition to fault-tolerant control

To improve fault detection and minimize altitude loss during the transition to fault-tolerant control, several strategies can be implemented. Firstly, reducing the reaction time of the fault detection system by optimizing algorithms and hardware can significantly decrease the time between fault occurrence and detection. Implementing predictive maintenance techniques can also help anticipate potential failures before they occur, enabling proactive fault detection. Additionally, enhancing the fault-tolerant control system's responsiveness and efficiency can aid in quicker transitions to the fault-tolerant mode, reducing the time the quadrotor spends in an unstable state. By integrating machine learning algorithms for fault prediction and detection, the system can become more adept at identifying issues early on, further minimizing altitude loss during transitions.

What are the potential trade-offs between increased drag for yaw rate control and the overall flight performance and efficiency of the quadrotor

The trade-offs between increased drag for yaw rate control and overall flight performance and efficiency of the quadrotor need to be carefully considered. While increased drag can help stabilize the quadrotor during fault-tolerant control by reducing the yaw rate, it can also lead to decreased flight performance and efficiency. The additional drag can impact the quadrotor's maneuverability, speed, and energy consumption, potentially limiting its capabilities in dynamic flight scenarios. Balancing the amount of added drag to achieve a controllable yaw rate without compromising the quadrotor's overall performance is crucial. It is essential to conduct thorough testing and analysis to find the optimal balance between yaw control and flight efficiency, ensuring that the quadrotor remains agile and responsive while maintaining stability during fault-tolerant operations.

How could the fault-tolerant control strategies be extended to handle other types of failures beyond rotor faults, such as sensor or actuator failures

Extending fault-tolerant control strategies to handle other types of failures beyond rotor faults, such as sensor or actuator failures, requires a comprehensive approach. For sensor failures, redundant sensor systems can be implemented to ensure data integrity and reliability. By incorporating sensor fusion techniques and advanced algorithms, the quadrotor can adapt to sensor failures by relying on alternative sensor data. Actuator failures can be addressed by implementing redundant actuators or control surfaces, allowing the quadrotor to redistribute control authority in the event of a failure. Advanced fault detection algorithms can be designed to detect sensor or actuator anomalies and trigger appropriate fault-tolerant control strategies. By integrating robust fault detection mechanisms and adaptive control strategies, quadrotors can be equipped to handle a wide range of failures beyond rotor faults, enhancing their resilience and safety in various operational scenarios.