An efficient sub-optimal motion planning method for attitude manoeuvres

A motion planning technique for efficiently generating smooth spacecraft attitude slew manoeuvres is presented. The attitude trajectory (using quaternions) is shaped by a polynomial, determined by matching prescribed boundary conditions and the manoeuvre time. This method allows constraints such as limits on velocity, acceleration, jerk, and torque to be evaluated via inverse dynamics. Pointing constraints are also considered. A spin-to-spin case is presented whereby an axisazimuth parameterisation is used. The problem of time minimization (within the set of trajectories defined by the given polynomials) is addressed, and a method for analytically estimating the minimum time of a manoeuvre is proposed. The method requires low computational capacity, and a comparison with optimal control solutions shows its relative performance.