  Vision-based tactile sensors have gained extensive attention in the robotics
community. The sensors are highly expected to be capable of extracting contact
information i.e. haptic information during in-hand manipulation. This nature of
tactile sensors makes them a perfect match for haptic feedback applications. In
this paper, we propose a contact force estimation method using the vision-based
tactile sensor DIGIT, and apply it to a position-force teleoperation
architecture for force feedback. The force estimation is done by building a
depth map for DIGIT gel surface deformation measurement and applying a
regression algorithm on estimated depth data and ground truth force data to get
the depth-force relationship. The experiment is performed by constructing a
grasping force feedback system with a haptic device as a leader robot and a
parallel robot gripper as a follower robot, where the DIGIT sensor is attached
to the tip of the robot gripper to estimate the contact force. The preliminary
results show the capability of using the low-cost vision-based sensor for force
feedback applications.
