This paper addresses automatic assembly with passive rather than active compliant devices. Previous work has shown that in an ideal manufacturing environment three assembly primitives (prismatic insertions, threaded fits and general path insertions) exhibit a high level of difficulty. None of these are reliably assemblable under sensor-based force control or with an ordinary remote center compliance (RCC) device. In this paper, the authors extend the science of part mating and apply dexterity theory to synthesize a passive assembly device for precision fits of three-dimensional prismatic parts. This spatial remote center compliance (SRCC) obviates sensor-based and force control approaches to precision assembly of non-axisymmetric parts.>

The authors introduce the slide motion scheme, which provides smooth movement of the endoscope stem with only three continuously controlled degrees of freedom. Such movement is accomplished by implementing a series of relative motions between an outer tube and intermittently stiff spines insides. The strength and stability of the locking mechanism, which exhibits the property of intermittent stiffness, is also discussed.>