An electro-magnetic actuator, consisted of a runner, a pair of electro-magnets and two stators, is developed for attenuating the engine-induced vibration transmitted to passenger vehicle chassis. It features that it is compact to be fit into the limited space and yet, it possesses high efficiency and wide frequency bandwidth for effective control of engine vibrations in standard size passenger cars.
An electronic circuit device is also developed such that the displacement between the electro-magnet pair and the target can be estimated from measurement of current to the coil only. It is found that the resolution and frequency bandwidth of the displacement estimator are about 5㎛ and 0 to 300Hz, respectively. The electro-magnetic actuator with the current feedback is capable of attenuating the vibration over the frequency range of 150 to 300Hz, which is satisfactory for applications of interest.
To check the control performance of the prototype current feedback electro-magnetic actuator, vibration control of a cantilever beam at its free end is attempted using the normalized filtered-X LMS algorithm, when the beam is disturbed at its mid span by an exciter and the prototype actuator is mounted at its free end.. Experimental results confirm that the beam vibration is well attenuated over the frequency range of 150 to 300Hz.
