Cascaded Vibration Isolation Control for Air Bearings
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Solution Overview
Problem
Existing vibration isolation systems with air bearings face challenges in effectively counteracting high-frequency vibrations due to slow pneumatic control loops and high current draw from actuators, which operate independently and can counteract pneumatic control.
Innovation Solution
A cascaded control system where the fluid pressure control loop and actuator control loop are connected, with the output of one control device serving as input to the other, allowing for coordinated control of fluid pressure and actuator activation to reduce current consumption and enhance vibration isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If pneumatic valves are used to control fluid pressure for level compensation, then the control system can handle slow movements and provide stable positioning, but the control bandwidth is limited to less than 3 Hz and high-frequency vibrations cannot be effectively counteracted
Solution Approach 1:
The control system is segmented into two independent control loops: a pneumatic control loop for low-frequency level compensation (bandwidth < 3 Hz) and an actuator control loop for high-frequency vibration isolation (bandwidth > 200 Hz). Each loop operates autonomously with its own sensors and actuators, allowing them to function at their optimal performance levels without interfering with each other.
Solution Approach 2:
The system dynamically assigns different control functions to different components based on frequency ranges. The pneumatic valves handle slow, large-scale position adjustments while the actuators handle rapid, high-frequency vibrations. This dynamic division allows the system to achieve both low-frequency stability and high-frequency responsiveness.
2Speed
If actuators are used to counteract rapid position changes and high-frequency vibrations, then control bandwidth exceeds 200 Hz, but the actuators draw a large amount of current and may counteract the pneumatic control
Solution Approach 1:
The control responsibilities are segmented by frequency range: the pneumatic loop handles low-frequency position changes while the actuator loop handles high-frequency vibrations. This segmentation allows actuators to operate only when needed for high-frequency compensation, significantly reducing their overall current consumption compared to continuous operation.
Solution Approach 2:
Both control loops use feedback from position sensors to determine when intervention is necessary. The actuators receive feedback signals that trigger activation only during high-frequency vibrations, allowing the system to minimize actuator operation and current draw while maintaining effective vibration isolation.
3Speed
If actuators operate independently of pneumatic control to address high-frequency vibrations, then rapid position changes can be reduced, but the actuators frequently counteract the pneumatic control
Solution Approach 1:
The control system is divided into two independent loops that operate in parallel without direct interaction. The pneumatic loop processes low-frequency signals while the actuator loop processes high-frequency signals, eliminating the counteraction problem that occurs when a single loop tries to handle both frequency ranges simultaneously.
Solution Approach 2:
The system dynamically separates control functions by frequency, allowing each control loop to optimize its response for its designated frequency range. This dynamic separation ensures that pneumatic control and actuator control work complementarily rather than conflicting with each other.
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 configuration reduces current drawn by actuators and improves vibration isolation by allowing the fluid pressure control to handle slow movements while actuators address rapid position changes, achieving control bandwidths that effectively counteract high-frequency vibrations.
Implementation Method 1
Vibration isolation systems having air bearings
Implementation Method 2
the compressed-air supply to the air bearings being controlled on the basis of the position detection
Implementation Method 3
one or more position sensors detect the position of the load to be mounted
Implementation Method 4
actuators which may be in the form of magnetic actuators
Implementation Method 5
actuators which may be in the form of magnetic actuators or piezo-actuators
Data Source
AI summary
The invention relates to a vibration isolation system, comprising at least one fluid bearing having a first control device in order to control the fluid pressure and having at least one actuator in order to compensate for position changes of the load to be isolated, which actuator is controlled by at least one second control device, wherein the input of one control device is connected to the output of the other control device.