  Monitoring the state of contact is essential for robotic devices, especially
grippers that implement gecko-inspired adhesives where intimate contact is
crucial for a firm attachment. However, due to the lack of deformable sensors,
few have demonstrated tactile sensing for gecko grippers. We present Viko, an
adaptive gecko gripper that utilizes vision-based tactile sensors to monitor
contact state. The sensor provides high-resolution real-time measurements of
contact area and shear force. Moreover, the sensor is adaptive, low-cost, and
compact. We integrated gecko-inspired adhesives into the sensor surface without
impeding its adaptiveness and performance. Using a robotic arm, we evaluate the
performance of the gripper by a series of grasping test. The gripper has a
maximum payload of 8N even at a low fingertip pitch angle of 30 degrees. We
also showcase the gripper's ability to adjust fingertip pose for better contact
using sensor feedback. Further, everyday object picking is presented as a
demonstration of the gripper's adaptiveness.
