Frequency-Optimized Space-Time Contours for Vibration Avoidance
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Solution Overview
Problem
Existing methods for minimizing vibrations in automated machinery are limited in effectiveness, often increasing costs and design complexity, and can distort space-time contours, leading to reduced machine performance and throughput.
Innovation Solution
The development of frequency-optimized space-time contours, created by concatenating polynomial segments, which suppress energy at specific frequencies without post-filtering, allowing machine elements to follow desired contours while minimizing vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If more energy is applied to the mechanism to operate faster, then the operating speed increases, but the amplitude of vibrations increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal space-time contours in a database before machine operation. These contours are designed to minimize vibrations at the source by optimizing the energy input profile, allowing the mechanism to operate at high speeds without exciting resonant frequencies. The controller simply retrieves and executes the pre-optimized contour, avoiding real-time vibration control complexity.
2Object-generated harmful factors
If engineering methods are used to design machine elements to not vibrate (special materials, increased mass/stiffness), then vibration is reduced, but the assembled cost and design effort increase
Solution Approach 1:
The patent replaces mechanical vibration control methods (special materials, increased mass, structural modifications) with a control-based approach. Instead of physically modifying the machine elements to reduce vibration, the system uses optimized space-time contours to control the energy input, thereby minimizing vibrations through intelligent actuation rather than mechanical design changes.
3Object-generated harmful factors
If frequency selective filters are placed in the energy source control path to remove exciting frequencies, then vibration is reduced, but errors are induced that limit faithful following of the space-time contour
Solution Approach 1:
The patent avoids the trade-off between vibration reduction and contour following precision by applying preliminary action in the contour design phase. The optimal space-time contours are pre-calculated to inherently minimize exciting frequencies while maintaining faithful following of the desired trajectory. This eliminates the need for post-hoc filtering that would compromise precision.
4Object-generated harmful factors
If space-time contours are filtered to remove exciting frequencies, then vibration is reduced, but the contour is distorted and machine performance is degraded
Solution Approach 1:
The patent resolves this contradiction by applying preliminary action during the contour generation phase. The optimal space-time contours are pre-calculated to simultaneously achieve vibration minimization and maintain the essential features of the desired trajectory. This eliminates the need for filtering operations that would distort the contour and reduce machine throughput.
Data Source
AI summary
A method for vibration avoidance in automated machinery produces actuator space-time contours that meet design objectives of the machinery while suppressing energy content at frequencies in the space-time contour, by concatenating multiple space-time contour segments together in such a way as to be mostly free of energy at the frequencies of interest while meeting other specified design goals. The segments used to construct these frequency-optimized-contours are a series of concatenated polynomial segments, the independent variable t being time. These segments can define the variable to be controlled (e.g. speed or distance) versus time, or define one of the controlled variable's time-derivatives (e.g., the slope of the speed vs. time, etc.). When these frequency-optimized-contours are fed as a command to a machine controller through an actuator or actuators, the energy at the frequencies of interest is low enough to avoid deleterious vibration from occurring while still meeting the machine performance objectives.