  The tactile sensing capabilities of human hands are essential in performing
daily activities. Simultaneously perceiving normal and shear forces via the
mechanoreceptors integrated into the hands enables humans to achieve daily
tasks like grasping delicate objects. In this paper, we design and fabricate a
novel biomimetic tactile sensor with skin-like heterogeneity that perceives
normal and shear contact forces simultaneously. It mimics the multilayers of
mechanoreceptors by combining an extrinsic layer (piezoresistive sensors) and
an intrinsic layer (a Hall sensor) so that it can perform estimation of contact
force directions, locations, and joint-level torque. By integrating our
sensors, a robotic gripper can obtain contact force feedback at fingertips;
accordingly, robots can perform challenging tasks, such as tweezers usage, and
egg grasping. This insightful sensor design can be customized and applied in
different areas of robots and provide them with heterogeneous force sensing,
potentially supporting robotics in acquiring skin-like tactile feedback.
