Variable structure control of globally feedback-decoupled deformable vehicle meneuvers

The use of Cayley-Rodrigues attitude parameters as kinematic variables is shown to yield a globally linearized and decoupled model of the equations of motion of a deformable body, wherein the structural deformation state appears only in the coefficients of the inverse transformation. It is then shown how commanded multi-axial attitude maneuvers can be encoded as switching surfaces for a variable structure control implementation of the corresponding computed slew torques, automatically modulated in response only to detected angular rate error signs, for accurate tracking in the presence of separately damped or even uncontrolled (but stable) structural deformations.