Hoisting Anti-Sway Optimization Through Secondary Sway Filtering
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Solution Overview
Problem
Existing anti-sway algorithms for hoisting appliances struggle to effectively control secondary sway phenomena, which have a higher frequency and are difficult to suppress, leading to reduced efficiency and productivity due to the need to stop the hoisting operation until the sway subsides.
Innovation Solution
A method and apparatus that utilize a frequency domain analysis to identify primary and secondary sway frequencies, applying a lowpass filter to reject secondary sway frequencies and a highpass filter to detect secondary sway, enabling safer and more efficient load transport by filtering out secondary sway components from the measured angle signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing anti-sway algorithms are used to control primary sway, then primary sway is reduced, but secondary sway remains uncontrolled and reduces effectiveness
Solution Approach 1:
The patent segments the sway control problem into two distinct frequency components: primary sway (lower frequency) and secondary sway (higher frequency). By applying frequency domain analysis and separate filtering strategies for each component, the system can address secondary sway independently without interfering with primary sway control, thereby resolving the contradiction where primary sway control was effective but secondary sway remained problematic.
Solution Approach 2:
The patent applies a partial action approach by selectively filtering only the problematic secondary sway frequency components while leaving the primary sway control unchanged. Instead of redesigning the entire anti-sway algorithm, the system applies a supplementary highpass filter to target specifically the higher frequency secondary sway phenomena, achieving improved effectiveness without overhauling the existing primary control mechanism.
2Reliability
If the hoisting operation is stopped to wait for secondary sway to subside, then safety is maintained, but productivity is reduced
Solution Approach 1:
The patent implements preliminary action by detecting and filtering secondary sway components before the load deposition phase. The frequency domain analysis and highpass filtering are applied continuously during operation, identifying secondary sway early and mitigating its effects in advance. This allows the system to proceed with load deposition without waiting for secondary sway to subside naturally, thereby maintaining safety while improving productivity.
Solution Approach 2:
The system employs feedback through continuous frequency domain analysis of the sway signal. By monitoring the higher frequency components in real-time and applying adaptive filtering based on detected secondary sway characteristics, the system can determine when it is safe to proceed with load deposition without requiring operators to wait for sway to subside, thus resolving the contradiction between safety and productivity.
3Difficulty of detecting and measuring
If frequency domain analysis is applied to identify sway frequencies, then secondary sway can be detected, but system complexity increases
Solution Approach 1:
The patent introduces an intermediary approach by using frequency domain analysis as a mediating layer between the raw sway signal and the control system. Instead of directly analyzing complex time-domain signals, the system transforms the signal into the frequency domain where secondary sway components can be easily identified and separated. This intermediary transformation simplifies the detection process while maintaining system manageability through standard signal processing techniques.
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 allows for precise control of secondary sway, enhancing the safety and productivity of hoisting operations by ensuring the load can be safely deposited only when secondary sway is below a threshold, thus improving the efficiency of anti-sway algorithms.
Implementation Method 1
filtering said time-domain signal representative of a measured angle of the load with respect to a vertical Z-axis by a lowpass filter designed to reject said identified secondary sway frequency
Implementation Method 2
performing a frequency domain analysis on said recorded time-domain signal to estimate frequency components of said time-domain signal
Data Source
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AI summary
For optimizing an anti-sway algorithm for the transport of a load (6) by a hoisting appliance spanning a hoisting area and comprising a trolley (2), a reeving system and a tool (4) handling the load, a control device is able to: record (S1a) a time-domain signal representative of a measured angle of the load (6) with respect to a vertical Z-axis during operation of the hoisting appliance, perform (S1b) a frequency domain analysis on the recorded time-domain signal to estimate its frequency components, identify (S1c) a primary sway frequency and a secondary sway frequency of the hoisting appliance among the estimated frequency components, filter (S2) the time-domain signal representative of a measured angle of the load with respect to a vertical Z-axis by a lowpass filter designed to reject the identified secondary sway frequency, transport (S3) the load (6) in the hoisting area by applying the anti-sway algorithm to the filtered signal.