Visual Tactile Sensor Based on Infrared Controllable Variable Stiffness Structure

To ensure smooth and precise operations during soft robot-assisted surgery, the force feedback of the robot is very important. Although some tactile sensors have been developed and used in surgery, there are limitations that make completing basic sterilization procedures difficult, such as the need for a complex structure or additional hardware. To address these problems, we propose a vision-based tactile sensor in this paper. The hardware structure is built on an endoscope system, without requiring any complex and experiment hardware, complex wiring, or mechanical interaction between the sensing system and tissues. The probe is made of highly biocompatible NiTi wire with polydopamine (PDA) coating and polymer-based markers. The proposed visual tactile sensor functions by extracting tactile information from images through a designed algorithm. The critical parameters of the core algorithms used for the sensor are discussed. The performance results demonstrate that the sensor can successfully record the interaction force, and its measuring range can be regulated by infrared irradiation. The sensor can potentially be used in robotic endoscopy to provide force feedback for soft robotic systems used in surgery, diagnosis, and drug delivery.