Optimal design of a semi-active isolation hexapod platform

Minimisation of low-level mechanical disturbances propagating through a satellite’s structure is crucial for missions employing high-precision pointing instruments, such as space interferometers and optical sensors. Performance degradation can be avoided by dynamically decoupling them from vibration-emitting onboard mechanisms. Hexapod platforms are well-suited for the purpose, but high system complexity, power requirements and mass tend to make them impractical. Here, a design approach for hexapod platforms intended specifically for spacecraft microvibration mitigation is proposed. The drawbacks of active control and actuation are circumvented by employing negative resistance electromagnetic shunt dampers (EMSDs). They offer similar performance, while being essentially passive in operation. An intrinsic limitation in high-frequency isolation of passive hexapods is addressed by substituting the common universal-spherical link joints with a universal-planar pair. A non-standard strut topology is demonstrated, such that purely linear motion within each strut is achieved with minimal off-axis moving mass. Finally, preliminary physical test data of the device is shown.