Efficient Large Multibody Flight Dynamic Simulation Through Improved Nonlinear Control Constraint Stabilization

Some air vehicles are configured such that major components exhibit relative motion with respect to one another where this relative motion significantly affects vehicle motion. In these cases, multibody flight dynamics is needed to adequately model system dynamics. This paper reports on a numerically efficient and versatile method for multibody flight dynamic simulation where the air vehicle is idealized as a collection of rigid bodies connected together by a set of joints. The method uses constrained coordinates with a constraint stabilization method based on a nonlinear control framework. The key innovation lies in relating the connections of the rigid bodies to an undirected graph and its adjacency matrix. By reordering connections, the bandwidth of the adjacency matrix can be minimized leading to substantial computational improvements. These improvements are applied to several air vehicle systems to highlight the computational benefits of the proposed technique.