Electrohydraulic Actuator Oscillation Suppression in Rolling
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Solution Overview
Problem
Rolling installations, particularly cold rolling lines, experience undesirable 3rd-octave oscillations leading to mechanical damage and defects in the rolled material, which reduce productivity and quality.
Innovation Solution
A method utilizing an electrohydraulic actuating element with a rated flow rate of ≥50 l/min, characterized by a magnitude drop of ≤3 dB and phase lag satisfying specific conditions at frequencies ≥80 Hz, is used to suppress oscillations by acting on hydraulic actuators for roller engagement, incorporating a regulator with a mathematical control rule and non-linear compensation to maintain controlled variables at nominal values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rolling speed is reduced to suppress oscillations, then oscillation damage is reduced, but productivity decreases
Solution Approach 1:
The oscillation suppression system acts preemptively by detecting oscillations at their onset and applying counteracting forces through the hydraulic actuator before the oscillations can cause significant damage. This allows the rolling process to continue at normal speed without needing to reduce throughput, as the harmful oscillations are neutralized in real-time rather than preventing them by slowing down.
Solution Approach 2:
The system continuously monitors rolling parameters and feeds this information back to the controller, which adjusts the hydraulic actuator in real-time to counteract detected oscillations. This closed-loop feedback mechanism enables the system to maintain both high productivity and oscillation suppression by dynamically responding to oscillation conditions without requiring speed reduction.
2Reliability
If conventional actuators are used for roller engagement, then device complexity is low, but oscillation suppression effectiveness is insufficient
Solution Approach 1:
The patent employs a hydraulic actuator system to provide the rapid, precise force control needed for effective oscillation suppression. The hydraulic system enables quick response times and fine force modulation that conventional mechanical actuators cannot achieve, directly improving oscillation suppression effectiveness while accepting the inherent complexity of hydraulic systems as necessary for this high-performance application.
Solution Approach 2:
The actuator system is designed with dynamic characteristics optimized for oscillation suppression, including a bandwidth of at least 80 Hz and specific phase lag characteristics. This dynamic design allows the actuator to respond effectively to high-frequency oscillations, achieving superior suppression performance compared to conventional static or low-bandwidth actuators.
3Speed
If electrohydraulic actuating element with high rated flow rate is used, then oscillation suppression response speed improves, but device complexity and cost increase
Solution Approach 1:
The patent specifies particular parameter ranges for the electrohydraulic actuating element, including a rated flow rate of at least 50 l/min and a bandwidth of at least 80 Hz. These parameter specifications ensure sufficient response speed for oscillation suppression while providing clear design guidelines that prevent unnecessary over-engineering and excessive complexity.
Solution Approach 2:
The patent references established design patterns and specifications from prior art (EP 1 457 274 A2) for the electrohydraulic actuating element, utilizing proven configurations that have demonstrated effective oscillation suppression. This approach allows implementation of high-performance response without reinventing complex systems, as the design follows established successful patterns.
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 suppresses 3rd-octave oscillations, improving the quality and productivity of the rolled material by rapidly identifying and addressing oscillations with precise control, reducing mechanical damage and surface defects.
Implementation Method 1
the manipulated variable is supplied to an electrohydraulic actuating element and this actuating element acts on at least one hydraulic actuator for the roller engagement
Data Source
AI summary
A method and an apparatus for suppression of oscillations in a rolling installation is described. By means of a hydraulic roller engagement third-octave oscillations are effectively suppressed, thus making it possible to improve the quality of the rolled material and/or the productivity of the rolling installation. A manipulated variable is supplied to an electrohydraulic actuating element that acts on at least one hydraulic actuator for the roller engagement and has a rated flow rate of ≧50 l/min. At least a portion of the frequency response at frequencies f≧80 Hz has a magnitude drop of ≦3 dB, and the phase lag φ in this frequency range satisfies the conditions f≧19·{square root over (φ)}+3.1·10−6·φ4 and φ<90°.