Design and Assessment of 3-DOF Nano-Gimbal for Spatial Manipulation

High-precision spatial manipulation and measurement require high-ratio vibration reduction and high positioning accuracy devices, in the presence of multi-degree-of-freedom (MDOF) vibrations and varying direction payload. In this paper, to ensure the positioning accuracy of the end-effector, a 3-DOF nano-gimbal is designed, which integrates a proposed 3-DOF tuned mass damper (TMD) for vibration suppression and a flexure-based nanopositioner for steady-state precision. Furthermore, as the critical part of vibration suppression, the modeling and design of 3-DOF TMD are analyzed and discussed in detail, considering both passive and active cases. First, the design and modeling of a 3-DOF nano-gimbal are presented, which is modeled by the modal decomposition method to obtain a set of decoupled motion equations. Then, the TMD is parameterized and optimized, where the passive case is designed by harmonic response methods, and the control law of the active case is designed by equivalent dynamics coefficients with state estimation. Finally, the performances of TMD and active tuned mass damper (ATMD) are evaluated by a set of simulations, including frequency and time domain assessments.