A Pneumatic Haptic Feedback Actuator Array for Robotic Surgery or Simulation

Robot-assisted minimally invasive surgery (MIS) offers improved range of motion over standard laparoscopic techniques, but is characterized by a total loss of haptic feedback, requiring surgeons to rely solely on visual cues. Pneumatic tactile displays have many advantages, including low mass, low cost, compact size, and adaptability. A pneumatic haptic feedback actuator array has been developed that is suitable for mounting unto surgical robotic tools. The balloon actuators consist of spin-coated thin-film silicone membranes and molded substrates with cylindrical channels. Human perceptual tests were conducted on balloon diameters ranging from 0.75 to 2.0 mm to determine the optimal size that can be effectively detected. The control system was programmed to sequentially inflate a single balloon to one of the three levels, 100% (full hemispherical deformation), zero, 50% (half deformation), and 0% (no inflation). Blinded subjects (n=5) were asked to determine which of the two inflation levels was higher. Test results suggest that balloon diameters greater than 1.0 mm can deliver high detection accuracy. This indicates that pneumatic balloon-based actuation is a viable solution for generating haptic feedback. In addition to surgical applications, many other fields such as virtual reality-based simulators and neuroprosthetics can benefit from this technology.