Novel force-sensing system for minimally invasive surgical instruments

A Modular 3-Degrees-of-Freedom Force Sensor for Robot-Assisted Minimally Invasive Surgery Research

Effective force modulation during tissue manipulation is important for ensuring safe, robot-assisted, minimally invasive surgery (RMIS). Strict requirements for in vivo applications have led to prior sensor designs that trade off ease of manufacture and integration against force measurement accuracy along the tool axis. Due to this trade-off, there are no commercial, off-the-shelf, 3-degrees-of-freedom (3DoF) force sensors for RMIS available to researchers. This makes it challenging to develop new approaches to indirect sensing and haptic feedback for bimanual telesurgical manipulation. We present a modular 3DoF force sensor that integrates easily with an existing RMIS tool. We achieve this by relaxing biocompatibility and sterilizability requirements and by using commercial load cells and common electromechanical fabrication techniques. The sensor has a range of ±5 N axially and ±3 N laterally with errors of below 0.15 N and maximum errors below 11% of the sensing range in all directions. During telemanipulation, a pair of jaw-mounted sensors achieved average errors below 0.15 N in all directions. It achieved an average grip force error of 0.156 N. The sensor is for bimanual haptic feedback and robotic force control in delicate tissue telemanipulation. As an open-source design, the sensors can be adapted to suit other non-RMIS robotic applications.

Bone Conduction Headphones for Force Feedback in Robotic Surgery

Bone conduction headphones (Fig. 1) offer the unique ability to provide auditory information to the user without obstructing external sounds. We apply this technology to robotic surgery to provide the surgeon with force feedback information with minimal distraction. The device is evaluated by pairing it with a force sensor that is attached to a suture pad. Four participants were tasked to complete 25 sutures on the suture pad while either receiving no feedback or audio, visual, or combined feedback that represents the magnitude of their applied force. Trials performed with bone conducting headphones had noticeable improvements compared to previous trials without feedback, while the most noticeable improvements were observed for cases with both visual and auditory feedback. Auditory feedback may have an important role in a robotic surgery setting and bone conduction headphones may enable this form of feedback with minimal distraction.