  A basic task in the design of a robotic production cell is the relative
placement of robot and workpiece. The fundamental requirement is that the robot
can reach all process positions; only then one can think of further
optimization. Therefore an algorithm that automatically places an object into
the workspace is very desirable. However many iterative optimzation algorithms
cannot guarantee that all intermediate steps are reachable, resulting in
complicated procedures. We present a novel approach which extends a robot by a
virtual prismatic joint - which measures the distance to the workspace - such
that any TCP frames are reachable. This allows higher order nonlinear
programming algorithms to be used for placement of an object alone as well as
the optimal placement under some differentiable criterion.
