Three dimensional delayed resonator of Stewart platform type for entire absorption of fully spatial vibration

Abstract

The paper deals with a novel design and investigation of a compact six degrees of freedom active vibration absorber with six identical eigenfrequencies. The objective is to entirely suppress vibration of a machine structure with six motion components, three translational and three rotational. The geometry of the spatial unifrequency absorber is based on a Stewart platform structure equipped with six active legs. Variants of this structure are analyzed. The six identical eigenfrequencies are finally reached by exerting active forces by actuators in the absorber legs, which actually produce active negative torsional stiffness. Achieving the unifrequency absorber with the help of a correction feedback brings variability to an optimization of the absorber design solution. In the next step, an active delayed resonator feedback is implemented to compensate the damping and to correct stiffness imperfections of the legs. The overall concept and design procedure are validated on a simulation case study including spectral analysis of arising infinite-dimensional system.