Vibration suppression using piezoelectric actuator-based active flexure joints for high precision operations

Flexure couplings are alternatives to conventional mechanical joints, eliminating tribological effects and joint reversal uncertainties. However, their low stiffness-induced dynamic errors hinder utilisation in high precision applications. Additionally, during operation flexure couplings can experience large deflections, leading to significant changes in their dynamic behaviour. An effective vibration control approach to minimise these effects is yet to be thoroughly investigated. To reduce resonance during operation, this work proposes to embed Micro-Fibre-Composites onto a passive flexure coupling structure, creating an active flexure coupling. A comparison between the mathematical model and measured system behaviour of passive and active flexure couplings shows the flexure coupling modification has insignificant impact on its elastic characteristics. Therefore, the robust mathematical representation of a system containing a passive flexure coupling is valid for designing feedforward motion control of an active flexure coupling. However, the performance of the active flexure coupling in vibration suppression is significant and demonstrated in both fixed poses and continuous motion-tracking of a two-link actuated system. This includes large deflections of the flexure coupling with a variation of the tip angle from −34.5^∘ to 37.2^∘. By implementing active flexure couplings into automated systems, high precision and high-value applications can be achieved.