An electro-magnetic actuator, consisting of a runner and a pair of facing electro-magnets, is developed for vibration control of structures. To enhance the linear motion of the actuator runner, the linear guide with oil-less bearings is used and the shape of runner is designed such that its mass moment of inertia is maximized. The prototype of electromagnetic actuator stabilized with a PD controller is tested to evaluate the vibration control capability when the actuator is mounted on the free end of a cantilever beam and the periodic plus random disturbance force is given near the mid-span. The control performance of the actuator is found to be excellent in attenuating the sustained vibration, when the Filtered-X LMS algorithm and the P control action are simultaneously adopted to control the beam response to the periodic and random disturbances, respectively.
As a practical application of the developed actuator, vibration control of the passenger vehicle chassis is attempted with the actuator mounted on the chassis near the engine mount position. The Filtered-X LMS algorithm alone is used to control the chassis vibration transmitted through the engine mount. Experimental results indicate that the chassis vibration associated with the integer multiples of 0.5X harmonics are effectively attenuated over the frequency range of 100 to 400 Hz.
