UAV Tethered Payload Oscillation Damping During Winch Operations
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Solution Overview
Problem
Unmanned aerial vehicles (UAVs) face challenges in damping oscillations of payloads coupled to tethers during winch operations, which can affect stability and precision in payload delivery.
Innovation Solution
The implementation of a control system that switches the UAV to a forward flight mode to induce drag on the payload, or reduces flight stabilization along certain dimensions to dissipate energy and dampen oscillations, during tether retraction and deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the UAV maintains hover flight mode with full flight stabilization, then the payload position is held stable, but oscillations of the payload are amplified and cannot be damped
Solution Approach 1:
The patent intentionally introduces aerodynamic drag on the payload by transitioning to forward flight mode or reducing flight stabilization. This converts the harmful oscillations into beneficial damping effects, where the drag force dissipates oscillation energy and stabilizes the payload during tether operations
Solution Approach 2:
The system dynamically adjusts the flight mode and stabilization level based on the operational phase. During tether retraction or deployment, the UAV reduces stabilization and enters forward flight to damp oscillations, then returns to hover mode with full stabilization when precise position holding is required
2Object-generated harmful factors
If the UAV transitions to forward flight mode to induce drag on the payload, then oscillations are damped, but energy consumption increases
Solution Approach 1:
The damping maneuver is applied periodically and temporarily only when needed during tether retraction or deployment phases. The system monitors the operational state and activates forward flight mode with reduced stabilization only during these specific phases, then returns to normal hover mode, avoiding continuous energy expenditure
Solution Approach 2:
The system changes flight parameters (velocity, stabilization level) temporarily to induce damping. By increasing forward velocity and reducing stabilization gain during critical phases, the system achieves oscillation damping with minimal energy input, then returns to energy-efficient hover mode
3Object-generated harmful factors
If the UAV reduces flight stabilization to dampen oscillations, then payload oscillations are reduced, but position holding precision deteriorates
Solution Approach 1:
Reduced stabilization is applied temporarily only during tether retraction or deployment when oscillations occur. Once the tether operation completes and the payload stabilizes, the system restores full flight stabilization to regain precise position holding capability
Solution Approach 2:
The stabilization level is dynamically adjusted based on the operational phase. During tether operations, stabilization is reduced to allow damping; during payload delivery or positioning phases, full stabilization is restored to ensure precision
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
These techniques effectively dampen payload oscillations, enhancing the stability and precision of payload delivery operations, particularly during the retraction and deployment phases of the tether.
Implementation Method 1
switch to a forward flight mode in which movement of the UAV results in drag on the payload, thereby damping the oscillations due to the drag
Implementation Method 2
reduce an extent of flight stabilization along at least one dimension, thereby resulting in damping of the detected oscillations due to energy dissipation during movement of the UAV along the at least one dimension
Data Source
AI summary
Described herein are methods and systems to dampen oscillations of a payload coupled to a tether of a winch system arranged on an unmanned aerial vehicle (UAV). For example, the UAV's control system may dampen the oscillations by causing the UAV to switch to a forward flight mode in which movement of the UAV results in drag on the payload, thereby damping the oscillations. In another example, the control system may cause the UAV to reduce an extent flight stabilization along at least one dimension, thereby resulting in damping of the detected oscillations due to energy dissipation during movement of the UAV along the dimension. In this way, the control system could select and carry out one or more such techniques, and could do so during retraction and/or deployment of the tether.