Shipboard Winch Maintains Constant Line Tension for Probe Depth Control
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Solution Overview
Problem
Existing winches for oceanographic profiling in shallow water lack reliability due to line tangling and inability to maintain constant tension without a communication cable, especially in variable weather conditions and unknown vessel velocity, which complicates achieving accurate depth profiles without a priori information on ship speed.
Innovation Solution
A micro-processor controlled winch that maintains minimal but constant line tension during the unspooling process, using a tension meter and controller to correlate descent time with depth, allowing for predictable probe descent and eliminating the risk of line tangling, even in free-fall conditions, without the need for a communication cable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a data cable is included to communicate depth data and control probe descent, then collision prevention capability is improved, but line weight and winch size increase significantly
Solution Approach 1:
The patent removes the data cable from the system entirely, extracting the communication function and replacing it with a timing-based depth estimation method. The probe operates autonomously without real-time communication, eliminating the heavy cable while maintaining safety through pre-calculated descent profiles based on constant tension control.
Solution Approach 2:
The patent replaces the mechanical/electrical communication system (data cable) with a computational approach using tension meter data and timing calculations. Depth is determined through algorithmic estimation based on measured tension and descent time rather than direct electronic communication.
2Speed
If line is rapidly unspooled to enable free-fall descent, then descent speed is improved, but line tangling occurs compromising reliability
Solution Approach 1:
The patent implements continuous feedback control by monitoring line tension throughout the deployment. The tension meter provides real-time data that feeds back to the control system, allowing dynamic adjustment of unspooling rate to maintain constant tension and prevent tangling while achieving rapid descent.
Solution Approach 2:
The patent transitions from static, fixed-rate unspooling to dynamic, adaptive control where the unspooling rate continuously adjusts based on measured tension. This dynamic approach allows the system to respond to changing conditions and maintain optimal descent performance without tangling.
3Measurement precision
If constant line tension is maintained during unspooling, then depth measurement accuracy is improved, but control system complexity increases
Solution Approach 1:
The patent enables the system to self-regulate tension through automated feedback control. The microprocessor continuously monitors tension meter readings and autonomously adjusts motor output to maintain constant tension, eliminating the need for manual intervention and reducing operational complexity despite increased electronic control capabilities.
Solution Approach 2:
The patent changes the control parameter from direct depth control to tension control. By maintaining constant tension as the primary control objective and using timing-based depth estimation, the system achieves accurate depth measurement through a different physical parameter (tension) that is more easily controlled and measured.
4Use of energy by moving object
If a communication cable is removed for light weight operation, then winch power requirements are reduced, but ability to prevent probe-collision with bottom is lost
Solution Approach 1:
The patent performs preliminary calculation of descent profiles and timing before deployment. Depth limits and descent rates are pre-determined based on target depth and environmental conditions, allowing the probe to autonomously follow a pre-planned trajectory that prevents bottom collision without requiring real-time communication.
Solution Approach 2:
The patent introduces timing and tension measurement as intermediary parameters that mediate between the winch control and depth achievement. Rather than directly controlling depth through cable feedback, the system uses tension and time as intermediaries to indirectly achieve accurate depth control and collision prevention.
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
The solution ensures reliable and accurate profiling of water columns with reduced risk of collision and line tangling, achieving depth accuracy within 10% without real-time depth feedback, independent of ship speed and environmental factors.
Implementation Method 1
The line is spooled onto a winch. The process comprises the following step of suspending, unspooling, and halting. In the unspooling step, the line from the winch is unspooled for releasing the probe and allowing it to descend within the column of water by negative buoyancy.
Implementation Method 2
A micro-processor controlled winch that maintains minimal but constant line tension during the unspooling process, using a tension meter and controller
Data Source
AI summary
A winch is employed for deploying a probe to a precise depth within a water column for making and recording physical measurement within such water column. More particularly, the winch rapidly unspools a line from an underway vessel, while maintaining minimal but constant line tension, as a probe, tethered to such line, descends within the water column in a “near” free-fall to a predetermined depth and then stops. The line lacks means for communicating its depth to the winch. The probe achieves a predictable descent behavior, even though it is tethered by a line to a winch onboard an underway vessel of unknown velocity and in variable weather conditions. The predictable descent behavior is achieved by maintaining a minimal constant tension on the line within a narrow range. The descent behavior of a probe in “near” free-fall has sufficient predictability to construct an algorithm to correlate descent time with depth. The predictability is sufficient to reduce the risk of collision between the probe and the water bottom to an acceptable level.