Dynamically isotropic Gough–Stewart platform for micro-vibration isolation in spacecrafts

This paper deals with the modeling, simulation, and experimental validation of a modified Gough–Stewart platform (MGSP) for vibration isolation, where the first six natural frequencies corresponding to the first six degree-of-freedom are nearly the same, enabling effective attenuation of the first six modes. The configuration is termed as dynamically isotropic and this work presents a geometry-based analytical approach to obtain the design parameters of the MGSP at its neutral position. The approach accommodates various payload configurations, including variable center of mass and mass/inertia properties. The validation of the design is demonstrated using a finite element software ANSYS${}^{\text{®}}$, and the model is further refined to incorporate flexural joints and structural damping. A prototype of the MGSP featuring flexural joints was tested, and it yielded experimental outcomes in close agreement with the finite element analysis results — the first six natural frequencies were close to the expected 29 Hz and vibration isolation of about 22 dB/octave. The close agreement among analytical, finite element, and experimental outcomes underscores the efficacy of our design approach and the suitability of an MGSP for micro-vibration isolation applications in spacecraft.