Pneumatically driven surgical instrument capable of estimating translational force and grasping force.

BACKGROUND: In robot-assisted minimally invasive surgery, feedback as well as sensing of translational and grasping forces allows surgeons to manipulate the robots using an appropriate force. However, there have been limited reports on single instruments capable of sensing both forces (translational force and grasping force), with the exception of instruments with electronic sensors. METHODS: In this study, a pneumatically driven surgical instrument capable of estimating both translational and grasping forces is developed. Our estimation method is based on the dynamics and pneumatic pressure changes of the instrument. For each force estimation, we applied a joint mechanism consisting of disks and a flexible backbone and constructed pneumatic driving systems, kinematic models, dynamic models, controller, and force estimator. RESULTS: We confirmed experimentally that the mean absolute error between the measured forces and the estimated translational and grasping forces is 0.2 N or less for any condition. From these results, it is seen that the mechanical interference between the joint actuation mechanism and grasper actuation mechanism is negligibly small. CONCLUSIONS: A method for estimating both forces was proposed, and experimental results confirmed the effectiveness of the method.

Evaluation of a pneumatic surgical robot with dynamic force feedback.

Robot-assisted surgery is limited by the lack of haptic feedback and increased operating times. Force scaling adjusts feedback transmitted to the operator through the use of scaling factors. Herein, we investigate how force scaling affects forces exerted in robotic surgery during simple and complex tasks, using a pneumatic surgical robot, IBIS VI. Secondary objectives were to test the effects of force scaling on operating time, depth of needle insertion and user satisfaction. Two novice males performed simple (modified block transfer) and complex (needle insertion) tasks under four scaling factors: 0.0, 0.5, 1.0 and 2.0. Single-blind experiments were repeated five times, with alternating scaling factors in random order. Increasing the scaling factor from 0.0 to 2.0 reduces forces in block transfer (p = 0.04). All feedback conditions reduce forces in needle insertion compared to baseline (0.5: p < 0.001, 1.0: p = 0.001, 2.0: p = 0.001). Time to complete block transfer is shorter for scaling factor 0.5 (p = 0.02), but not for 1.0 (p = 0.05) or 2.0 (p = 0.48), compared to baseline. Depth of needle insertion decreases consistently with incremental scaling factors (p < 0.001). Further reductions are observed upon augmenting feedback (0.5-2.0: p = 0.02). User satisfaction in block transfer is highest for intermediate scaling factors (0.0-1.0: p = 0.01), but no change is observed in needle insertion (p = 0.99). Increments in scaling factor reduce forces exerted, particularly in tasks requiring precision. Depth of needle insertion follows a similar pattern, but operating time and user satisfaction are improved by intermediate scaling factors. In summary, dynamic adjustment of force feedback can improve operative outcomes and advance surgical automation.