Crane Swing Control with Suspension-Length Resonance Filtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cranes fail to effectively reduce vibrations in loads due to resonance frequencies, particularly when considering the length of the sling wire rope, leading to inefficiencies in load handling and reliance on operator skill.
Innovation Solution
A crane system that computes resonance frequencies based on both wire rope suspension length and load center of gravity, generating filtered control signals to attenuate specific frequency components, adjusting the frequency range and attenuation rate based on the suspension length to account for variations in sling length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the resonance frequency is computed based only on wire rope suspension length, then the computation is simple, but the vibration reduction effectiveness deteriorates when the sling length ratio increases
Solution Approach 1:
The invention changes the parameters used in resonance frequency computation from only wire rope suspension length to include both suspension length and sling length. This parameter expansion allows accurate computation of resonance frequency across varying load configurations, maintaining vibration reduction effectiveness without excessive complexity increase.
Solution Approach 2:
The system implements feedback by continuously monitoring suspension length and sling length, then using this information to dynamically adjust the resonance frequency computation and filter characteristics. This closed-loop approach ensures accurate vibration reduction adapts to changing operational conditions.
2Device complexity
If the frequency range and attenuation rate are fixed, then the control system is simple, but the vibration reduction effectiveness deteriorates for varying suspension lengths
Solution Approach 1:
The invention makes the control system dynamic by adjusting filter characteristics (frequency range and attenuation rate) based on real-time suspension length measurements. This dynamic adaptation allows the system to maintain optimal vibration reduction performance across varying operational conditions while keeping the control architecture manageable.
Solution Approach 2:
The system changes control parameters (frequency range and attenuation rate) based on measured suspension length. This parameter adaptation ensures the filter remains effective across different operating conditions without requiring a completely different control system for each scenario.
3Device complexity
If the sling length is not considered in resonance frequency computation, then the computation remains simple, but the resonance frequency accuracy deteriorates
Solution Approach 1:
The invention expands the computation parameters to include both suspension length and sling length in the resonance frequency calculation. This dual-parameter approach significantly improves resonance frequency accuracy while maintaining computational efficiency through established mathematical models.
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
Effectively reduces vibrations in loads by accurately accounting for the resonance frequencies of both simple and double pendulum motions, enhancing load stability and handling efficiency.
Implementation Method 1
computes a resonance frequency of a swing of a load; generates a filtered control signal for the actuator, the filtered control signal being the control signal in which a frequency component in computed frequency range is attenuated with reference to the resonance frequency
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Provided is a crane that is capable of effectively suppressing oscillation related to the pendulum resonance frequency generated in a suspended load on the basis of the suspended length of a wire rope. The crane 1 calculates a suspended load oscillation resonance frequency ωx(n) determined on the basis of the suspended length L(n) of a wire rope (14·16), and generates a control signal C(n) for an actuator according to an operation signal, and, on the basis of the resonance frequency ωx(n), generates from the control signal C(n) a filtering control signal Cd(n) for the actuator. The frequency range of the attenuated frequency component and/or the percentage of attenuation is altered on the basis of the suspended length L(n) of the wire rope (14·16), which is the length of the wire rope plus sling to a position of a center of gravity of the load.