Active Lubrication Brakes in Tabletop and Hand-Held Haptic Surgical Drilling Simulators

Haptic user interfaces that provide both kinesthetic and vibrotactile feedback have strong potential to enhance a wide range of medical training simulations. Yet, designing such devices remains challenging due to constraints related to integration, workspace, cost, and the need for diverse feedback types. To address these issues, we investigated the applicability of a novel type of brake based on the active lubrication principle. This actuator is compact, low-cost, and able to deliver both kinesthetic and vibrotactile feedback. To demonstrate its advantages, we focused on maxillofacial drilling in surgical training. We designed, implemented and evaluated a one-degree-of-freedom drill mock-up embedded into a tabletop prototype able to render axial forces up to 4.5 N. To assess both the relevance of combined feedback and the suitability of this actuator for surgical simulation, we conducted two studies: one with fourteen non-surgeon participants and another with six maxillofacial surgeons. Results confirm the potential of this actuation approach for surgery simulators and highlighted the importance of combined kinesthetic and vibrotactile feedback to improve realism, user preference, and task performance. Based on the surgeons' feedback, we then proposed a redesigned brake, with an improved control method, implemented in a new hand-held version of a drill replica. Preliminary characterisation shows that the new prototype can render forces up to 5.5 N and produce higher vibration amplitudes than the initial design.