Dynamically Isotropic Gough-Stewart Platform Design with Flexural Joints

A dynamically isotropic Modified Gough-Stewart Platform (MGSP), with equal first six natural frequencies, is well-suited for micro-vibration isolation as it allows for the utilization of identical dampers, resulting in effective vibration isolation. In an earlier work, a novel geometry-based approach was developed to deduce the design parameters of a dynamically isotropic MGSP with conventional kinematic joints. In spacecraft applications, kinematic joints may introduce friction, backlash errors, and lubrication-related issues that can negatively impact the vibration isolation characteristics of the MGSP. In this work, an MGSP with flexural joints is considered, and different designs are evaluated by considering their dynamic isotropic index (DII), manufacturing feasibility, and static and dynamic characteristics. The DII is a critical metric, representing the ratio of the largest to the smallest natural frequency among the first six modes, quantifying the frequency spread. Simulations of the developed designs were performed in a finite element analysis software ANSYS. A prototype of the MGSP with flexural joints was built, and experiments were conducted to extract the frequencies associated with the \(\boldsymbol{X}\) , \(\boldsymbol{Y}\) , and \(\boldsymbol{Z}\) modes. The natural frequencies obtained through simulation range from 43–45 Hz and matched very closely with the experimental results. Additionally, a damping of 6–7 % across all modes was achieved. The agreement between the analytical, simulation, and experimental results validates our design approach and demonstrates its suitability for micro-vibration isolation applications in spacecraft.