Detailed explanation of the working principle of the isolation table: from passive isolation to active compensation

Introduction: The Core Secret of Vibration Isolation Platform Technology

Vibration is an invisible killer in precision experiments and industrial production, and the isolation table is the first line of defense against vibration interference. The development of vibration isolation technology has gone through an evolution from passive isolation to active compensation, from simple rubber pads to complex active control systems. This article will provide an in-depth analysis of the working principle of isolation tables, revealing how different types of isolation tables achieve vibration suppression and helping users understand the scientific principles behind isolation tables.

1、 Passive Vibration Isolation Platform: Basic Vibration Isolation Principle

1.1 Spring Mass System Theory

The core principle of passive isolation table is the spring mass system. When the vibration source is transmitted to the isolation table, the spring (or elastic element) undergoes deformation to absorb energy, and the mass block (platform surface) remains relatively stable due to inertia. The natural frequency of the system determines the isolation effect, and the lower the natural frequency, the better the isolation effect.

1.2 The role of damping materials

A simple spring system will amplify vibration at the resonance frequency, so damping materials are required to consume vibration energy. LeadTop’s solid-state isolation optical platform POT-P series adopts composite rubber damping technology, with a vertical natural frequency of 6.5-12Hz. The vibration energy is converted into thermal energy through internal friction of the material, effectively suppressing resonance peaks.

1.3 Typical Passive Vibration Isolation Platform Structure

LeadTop’s solid-state isolation optical platform POT-P series adopts a broadband damping structure platform, which can be made of honeycomb or superconducting magnetic isolation materials, and is equipped with a shear type multi-layer composite rubber isolation structure to effectively suppress surface resonance. The platform has a height of 800mm and supports manual leveling (± 10mm adjustment). The vertical/horizontal natural frequency is 6.5-12Hz, and the flatness of the platform is 0.05-0.1mm/㎡. The surface is matte treated with a roughness of 0.8-1.6 μ m, and the structure is stable with minimal maintenance. Suitable for instrument and equipment scenarios with low vibration requirements, such as microscopes, medical biology, and optical path testing.

2、 Air floating isolation table: the ultra-low frequency advantage of air springs

2.1 Working principle of air spring

The air flotation isolation table uses compressed air to form elastic support, and the compressibility of air makes it an ideal spring medium.

2.2 Automatic leveling system

The air flotation isolation platform is equipped with a pneumatic automatic leveling system, which detects the tilt of the platform through a height sensor and automatically adjusts the air pressure at each support point to achieve levelness. The leveling accuracy can reach ± 0.1mm, and the working pressure is 0.2~0.4MPa, ensuring that the table is always in an ideal state.

2.3 Innovation of Swing Rod Structure

The ZDT-B series of LeadTop’s air floating pendulum type vibration isolation optical platform adopts an innovative design of air spring+pendulum structure, utilizing the principle of a single pendulum to achieve a horizontal natural frequency as low as 1.0-1.5Hz (vertical 1.0-2.0Hz), with an isolation efficiency of 86-99% (5-10Hz). Supports pneumatic automatic leveling and ± 10mm height adjustment, equipped with a silent air compressor (<50dB), with a tabletop flatness of 0.05-0.1mm/㎡ and surface matte treatment. Suitable for precision scenes with extremely high vibration requirements such as microscopes and laser interferometry, providing an ultra stable operating environment for high-precision equipment.

2.4 Silent Air Supply System

The air flotation isolation table needs to be equipped with an air compressor. Modern products have achieved silent design, which will not affect the laboratory environment and provide a stable and clean air supply.

3、 Active Vibration Isolation Platform: Intelligent Vibration Compensation Technology

3.1 Sensor detection system

The core of the active isolation platform is high-precision sensors that monitor the vibration status of the platform in real time. Piezoelectric sensors can detect nanoscale displacement changes, convert mechanical vibrations into electrical signals, and transmit them to the control system, providing a data basis for active compensation.

3.2 Control Algorithm and Response

After receiving sensor signals, the control system calculates compensation force through PID or more advanced control algorithms, and drives the actuator to generate reverse vibration for cancellation.

3.3 Six degree of freedom fully active compensation

The high-end active isolation platform achieves fully active compensation for six degrees of freedom (three translations+three rotations).

3.4 Intelligent Control Function

The modern active isolation platform integrates multiple intelligent functions. LeadTop’s LVH-T15 heavy-duty active isolation platform is designed specifically for TEM/SEM, using electromagnetic actuators and four stage air spring composite technology to achieve six degrees of freedom vibration suppression across the 1-200Hz frequency range and eliminate building sway interference between 0.5-5Hz.

500kg ultra large load-bearing capacity, low-frequency attenuation> 35dB@5Hz (Corresponding to 90% isolation efficiency), 30ms step disturbance suppression, supports online modal analysis. Suitable for electron microscopy imaging, semiconductor detection, and life science fields, it significantly improves the resolution of cryo electron microscopy and FIB beam stability, making it an ideal isolation solution for heavy-duty precision instruments.

4、 Hybrid Vibration Isolation Platform: Integration of Active and Passive Technologies

4.1 Advantages of Composite Technology

The hybrid isolation platform combines the advantages of active and passive technologies, with the passive layer providing basic isolation and the active layer providing fine compensation.

4.2 Application scenario adaptation

The hybrid isolation table is suitable for scenarios that require extremely high vibration control requirements. Ultra precision equipment such as wafer inspection and femtosecond laser systems require wideband and high-efficiency isolation table solutions, and hybrid technology can simultaneously meet the requirements of low-frequency and high-frequency vibration suppression.

4.3 Performance and Cost Balance

Compared to pure active isolation platforms, hybrid isolation platforms reduce costs while ensuring performance.

Conclusion: The Continuous Evolution of Isolation Platform Technology

From passive isolation to active compensation, isolation table technology continues to develop and innovate. The passive isolation table is economical and practical, the air flotation isolation table has obvious advantages in ultra-low frequency, the active isolation table is intelligent and efficient, and the hybrid isolation table integrates multiple technological advantages. Users should choose the appropriate type of isolation table based on their specific needs. With the advancement of materials science and control theory, vibration isolation tables will continue to develop towards higher performance, lower cost, and greater intelligence, providing better vibration control solutions for precision experiments and industrial production.