Design, fabrication, optimization and evaluation of a multinodal tactile feedback system for teleoperated robot-assisted minimally invasive surgery.

摘要

Robot-assisted minimally invasive surgery has gained widespread use over the past decade, but the technique is limited by the absence of haptic feedback. A multinodal tactile feedback (MTF) system has been developed and mounted directly onto the da Vinci surgical robotic system. This system consists of a 3x2 element piezoresistive force sensor array, a pneumatic control system, and a tactile display with 3x2 balloon actuator array, which consist of a molded polydimethylsiloxane substrate with cylindrical channels and a spin-coated silicone film as the balloon membrane. Human psychophysical tests and mechanical characterization tests were performed on various actuator designs to determine the optimal configuration and performances of the tactile display. The results indicated that a 3.0 mm balloon was optimal to provide five distinct levels of tactile information to human fingers. An edge-to-edge spacing of 1.5 mm and a temporal response of 93 ms or greater both provided high detection accuracy. 3.0 mm balloons with 300 mum thick films produced linear pressure-balloon deflection responses (R2 = 0.98) over the 0 to 15 psi range, minimal hysteresis effects between inflation and deflation over 15,000 cycles, and consistent performance among actuators from various fabrication batches. The optimized tactile display was integrated with control system, single element sensor or sensor array to form a complete feedback system. This system was the first complete tactile feedback system known to be applied to a commercial robotic surgical system, and allowed the effect of direct tactile to tactile feedback in robot-assisted surgery to be evaluated for the first time. The evaluation tests demonstrated that the presence of tactile feedback significantly reduced grip force during robotic manipulation and that the reduction of force was not sustainable once the feedback was removed. Human perceptual tests were performed with the MTF system to evaluate the feasibility of MTF. High accuracy (>96%) of the force location, the static and dynamic direction tests suggest that MTF may be an effective means to improve robotic control and handling of tissues and other objects. The modular design of this system allows for adaptation to other robotic or mechanical systems without modification of the original software and hardware of these systems, including general robotic manipulation, prosthetic rehabilitation, virtual reality-based gaming and surgical training.