  This work presents a new version of the tactile-sensing finger GelSlim 3.0,
which integrates the ability to sense high-resolution shape, force, and slip in
a compact form factor for use with small parallel jaw grippers in cluttered
bin-picking scenarios. The novel design incorporates the capability to use
real-time analytic methods to measure shape, estimate the contact 3D force
distribution, and detect incipient slip. To achieve a compact integration, we
optimize the optical path from illumination source to camera and other
geometric variables in a optical simulation environment. In particular, we
optimize the illumination sources and a light shaping lens around the
constraints imposed by the photometric stereo algorithm used for depth
reconstruction. The optimized optical configuration is integrated into a finger
design composed of robust and easily replaceable snap-to-fit fingetip module
that allow for ease of manufacture, assembly, use, and repair. To stimulate
future research in tactile-sensing and provide the robotics community access to
reliable and easily-reproducible tactile finger with a diversity of sensing
modalities, we open-source the design and software at
https://github.com/mcubelab/gelslim.
