  We present an approach to robotic manipulation of unknown objects through
regulation of the object's contact configuration: the location, geometry, and
mode of all contacts between the object, robot, and environment. A contact
configuration constrains the forces and motions that can be applied to the
object; however, synthesizing these constraints generally requires knowledge of
the object's pose and geometry. We develop an object-agnostic approach for
estimation and control that circumvents this need. Our framework directly
estimates a set of wrench and motion constraints which it uses to regulate the
contact configuration. We use this to reactively manipulate unknown planar
objects in the gravity plane. A video describing our work can be found on our
project page: http://mcube.mit.edu/research/contactConfig.html.
