MINIMUM-TIME REORIENTATION OF A 2-DEGREE-OF-FREEDOM GYROSCOPE

The problem of time-optimal reorientation of the inner gimbal of a two -degree-of-freedom gimballed gyroscope mounted on a nonrotating base i s considered. The states in the gyro model are the gimbals' angles (nu tation is ignored). The model is nonlinear (not limited to small angle s), state constrained, control limited, and double input, double outpu t. A simple, explicit solution based on an intuitive observation is pr esented; it exploits the system's nonlinearity and channel coupling fo r attaining the minimum-time goal,It is analytically shown, in detail, that the solution satisfies the Maximum Principle and fulfills a suff icient condition for optimality based on the Hamilton-Jacobi-Bellman e quation.