Contact forces in spacecraft motion equations during docking and berthing

Spacecraft docking and berthing are a controlled on-orbit mechanical assembly process realized using active and passive docking units. Guiding surfaces of these units provide decreasing of lateral and angular misalignments during approach. Math models of contact interaction of these surfaces during docking and berthing can be divided into two classes. Contacts of two bodies (links of mechanisms and docking units) with several degrees of freedom and comparable inertia are considered in the first class of models as dynamical processes and described by differential equations of motion with temporary one-sided constrains. Contact simulation with constrain equations leads to differential-algebraic equations with less computational efficiency. A description of guiding surfaces contacts by theirs penetration and contact stiffness provides similar results with a high flexibility and computational efficiency of simulation. Penetration model based computing algorithms for contact kinematic parameters are considered in this paper...