A self-tuning adaptive-passive lever-type vibration isolation system

摘要

In this study, a novel self-tuning adaptive-passive lever-type vibration isolation system for base excitations is described. Due to inertial coupling within the vibration isolation system, an antiresonance frequency is generated, which depends on the amplification ratio of the lever. At this frequency, the instantaneous center of zero velocity of the lever coincides with the hinge that is under the payload. As a result, the payload experiences minimum amount of vibration. When the excitation frequency changes, the system changes the lever ratio so as to bring the antiresonance frequency to coincide with the excitation frequency to suppress the output vibration. The designed mechanical system does not require any electronic sensors or actuators. The self-tuning operation is enabled by an elastic fin type actuator powered by the input vibration rendering the system self-powered. The installation of the actuator enables it to act also as a sensor, so no additional vibration sensor is required. The equations of motion of the system are derived and the location of the instantaneous center is obtained analytically. Then, multi-body dynamic simulations are carried out to verify the self-tuning response of the system. A prototype incorporating a variable ratio lever, a softly suspended ground mass and an elastic fin type actuator is manufactured. Experimental results validate that the system always goes to antiresonance condition in the working frequency range.