Dynamic Vibration Test Device Control Stability
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Solution Overview
Problem
In dynamic test devices, the independent control of vibration by voice coil motors and static load by air springs leads to control instability, especially during low-frequency or quasi-statically varying vibration tests.
Innovation Solution
A dynamic test device and control method where both electrodynamic and pneumatic vibration means are controlled using the same control signal, ensuring vibration occurs within the quasi-static region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the voice coil motor and air spring are controlled independently, then each component can operate with its own optimal control characteristics, but control instability occurs during low-frequency or quasi-statically varying vibration tests due to frequency characteristic differences
Solution Approach 1:
The patent merges the control of the voice coil motor and air spring into a unified control system that operates based on the same control signal. This combination allows both components to work together harmoniously, eliminating the control instability that arises from independent control while maintaining the complementary advantages of each actuator across different frequency ranges.
Solution Approach 2:
The patent implements dynamic control where the control signals to both the voice coil motor and air spring are adjusted in real-time based on the vibration test requirements. The control system dynamically coordinates the output of both actuators, allowing smooth transitions between low-frequency (air spring dominant) and high-frequency (voice coil motor dominant) operation modes.
2Power
If the air spring bears the static load during vibration tests, then the voice coil motor can focus on dynamic vibration, but control instability occurs when the vibration load varies quasi-statically or at low frequencies
Solution Approach 1:
The patent applies partial action by having the air spring primarily handle the static load and low-frequency components, while the voice coil motor handles the high-frequency dynamic vibration. During quasi-static or low-frequency tests, the control system increases the air spring's contribution beyond its traditional static-only role, allowing it to partially compensate for the voice coil motor's limited low-frequency performance.
Solution Approach 2:
The patent changes the operational parameters of both actuators dynamically. The control system adjusts the air pressure in the air spring and the electrical input to the voice coil motor based on the vibration frequency and amplitude requirements. This parameter adjustment allows optimal performance across the full frequency spectrum while maintaining control stability.
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
This approach eliminates control instability when managing static loads applied by air springs, enhancing the stability and accuracy of vibration tests.
Implementation Method 1
electrodynamic first vibration means that reciprocates the vibration portion to vibrate the vibration portion
Implementation Method 2
pneumatic second vibration means that reciprocates the vibration portion to vibrate the vibration portion
Data Source
AI summary
An electrodynamic vibration testing system for shaking a specimen comprises a fixed section, a movable section which can reciprocate in a predetermined direction with respect to the fixed section, a voice coil motor for driving the movable section, a table attached to the movable section for fixing the specimen, an air spring which supports the movable section to the fixed section from below, and a reaction plate attached to the fixed section for sandwiching the specimen between the table, and the reaction plate.