  Active Force Control (AFC) is an important scheme for tackling high-precision
robotic assembly. Classical force controllers are highly surface-dependent: the
controller must be carefully tuned for each type of surface in contact, in
order to avoid instabilities and to achieve a reasonable performance level.
Here, we build upon the recently-developed Convex Controller Synthesis (CCS) to
enable high-precision assembly across a wide range of surface stiffnesses
without any surface-dependent tuning. Specifically, we demonstrate peg-in-hole
assembly with 100 micron clearance, initial position uncertainties up to 2 cm,
and for four types of peg and hole materials -- rubber, plastic, wood, aluminum
-- whose stiffnesses range from 10 to 100 N/mm, using a single controller.
