Module 5: Principles of Active Vibration Control
  Lecture 22: Introduction to Active Vibration Control: Organization
 


Vibration Isolation using AVC

  • Another traditional application of AVC is in the field of Vibration Isolation. In typical cases like vibration isolation of noisy machines - particularly in the low frequency range - could not be achieved by traditional isolators as the mass of the isolators will be prohibitively high.
  • AVC is of good use in such application as new actuators like Lead-Zirconate-Titanate based PZT actuators have high band-width.
  • Figure 22.3 shows the concept of an active suspension system.

Figure 22.4: Concept of Smart Suspension System

Highlights of the system

  • The excitation is applied in the bottom most plate simulating a typical vehicle excitation on a road.
  • The middle plate represents the chassis and is supported on a traditional spring-damper system (connected in parallel).
  • The active suspension is achieved due to the interaction between two magnets – a permanent magnet located on the top of the middle plate and an electromagnet situated on top of the permanent magnet at a distance ‘x' away with the help of a top supporting plate.
  • It can be shown that the electromagnetic force effective on the middle plate varies proportionately with the control current in the E-M actuator and is quite effective at a small distance (about 10-15mm).
  • Using a control current of about 600 mA and a phase-lead controller it is shown one can drop down the vibration amplitude from 20mm to 2mm in a frequency range of 2-30Hz.