Minimized Converging Single-Point (MConS) Kinematics: a Novel Approach to Fastening Detachable Spacecraft Structures

摘要

The process of connecting or detaching separate bodies in space can be aided very readily by the use of kinematics. A kinematic mounting system, as the definition will be used in the context of this topic, is a structural bond created solely by the geometry of a surrounding structure and a structure being bound. The use of kinematics can have very significant advantages over traditional fasteners like bolts and traditional clamps if certain features are utilized. The use of converging kinematics provides the highly beneficial feature of tending a system towards a certain stable equilibrium from a range of starting locations that meet the requirements of a set of initial conditions. Many space systems have a very apparent need for various levels of alignment in a fastening system where complex alignment mechanisms are difficult to actuate. In a convergent system such as the one in the theory being proposed, a force need only be applied in one direction and the binding structure will align the structure being bound using the available geometric surfaces leaving the child structure in a fastened, aligned position after the application of a force in a single direction. Convergent systems work in parallel with single-point kinematics where necessary. The term single point kinematics is referring to the utilization of only point contacts. Traditional optical kinematic systems utilize theoretical line-contacts. The advantages of using point contacts exclusively are in the conductive properties of single-point contacts. Single points of contact offer excellent thermal isolation which is a very desirable feature in many spacecraft applications. Depending on the load being applied to the structure, the contact patch between a convex mount and a theoretically flat female surface can be extremely small in which case the conductive resistance as a function of contact area will be approaching zero. Using single-point contacts, if the number of contact points is minimized, the thermal performance of the system can be maximized. The minimization of necessary contact points to constrain a system in three dimensions has been found through a geometric investigation to be mathematically related to the number of translation and rotation modes being acted against. This geometric analysis provides a theory as to the minimum number of points needed to constrain any system with forces acting in know modes of translation or rotation. The three main points of potential benefit for the system being proposed include the use of converging surfaces for aid in alignment and to allow for the potential use of single-point contacts to isolate the thermal conductance paths between two structures. Combined with these features a novel geometric analysis was performed to find the least number of contact points that were necessary to fully constrain a rigid body. In a system needing support or restriction in all three translation modes (X, Y, and Z) and all rotation modes (roll, pitch, and yaw) a kinematic bounding using single point contacts could be optimized to be a highly conductively isolated structural contact system.