| Summary: | Haptic feedback and motion tracking are still absent in the Robotic Minimally Invasive
Surgery (RMIS). The non-transparency between the master-slave system affects the
surgeon's situation awareness and safety assessment during an operation. Therefore,
there is a demand for developing miniature sensors to detect the tool-tissue interaction
in surgical robotics. Due to tighter space constraints in the flexible endoscopic robot, it
becomes much more challenging to advance sensors in such a robotic system. The
research aims to develop novel and practical solutions to realize force sensing and pose
sensing for flexible endoscopic surgical robots.
A single-axis force sensor (two versions), an integrated sensor-model approach, a three -axial force sensor have been proposed to capture the distal force in an endoscopic
surgical robot driven by Tendon-Sheath Mechanisms (TSMs). The single-axis force
sensor was integrated with the actuation mechanism, measuring the distal tension force
in real-time, with a sensitivity of 34.14 pm/N. The integrated sensor-model approach
has been validated in a 5-DoF (Degree of Freedom) grasper in both in-vitro tests and an
animal study (in a live porcine). This approach saves cost and space while maintaining
the robustness of the sensing system. Another three-axial force sensor has been further
explored to reflect the tool-tissue interaction forces, with a lateral force sensitivity up to
1757.438 pm/N. Validation tests have been conducted to show its measurement
capability of pulling force (0 N to 6 N), steering force (-3.5 N to 3 N), and lifting force
(-4.5 N to 4.5 N). Besides, real-time forces have been displayed on the surgeon's hand
through the haptic device, Omega7. In addition, a rotation angle sensor (RAS) has been
developed to detect a pivot joint's rotation angle in the articulated surgical grasper, with
a broad measurable range of angles [-47.8°, 39.1°] and a small bending radius down to
6.9 mm.
Apart from flexible endoscopic robots, the single-axis force sensor and the integrated
sensor-model approach can also be applied in TSM-driven or tendon-driven robotic
fingers/hands, wearable devices, surgical catheters, and rehabilitation devices. The
three-axial force sensor can also be shifted to a laparoscopic robot or a catheter, not
limited to the flexible endoscopic surgical robot. The RAS can also be used in
continuum robots or soft robots to detect the large bending deflection.
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