  We propose a method for dual-arm manipulation of rigid objects, subject to
external disturbance. The problem is formulated as a Cartesian impedance
controller within a projected inverse dynamics framework. We use the
constrained component of the controller to enforce contact and the
unconstrained controller to accomplish the task with a desired 6-DOF impedance
behaviour. Furthermore, the proposed method optimises the torque required to
maintain contact, subject to unknown disturbances, and can do so without direct
measurement of external force. The techniques are evaluated on a single-arm
wiping a table and a dual-arm platform manipulating a rigid object of unknown
mass and with human interaction.
