A technique is presented for creating continuously parameterized classes of feasible system trajectories. These classes, which are useful for higher-level vehicle motion planners, follow directly from a small collection of userprovided example motions. A dynamically feasible trajectory interpolation algorithm generates a continuous family of vehicle maneuvers across a range of boundary conditions while enforcing nonlinear system equations of motion as well as nonlinear equality and inequality constraints. The scheme is particularly useful for describing motions that deviate widely from the range of linearized dynamics and where satisfactory example motions may be found from off-line nonlinear programming solutions or motion capture of human-piloted flight. The interpolation algorithm is computationally efficient, making it a viable method for real-time maneuver synthesis, particularly when used in concert with a vehicle motion planner. Experimental application to a three-degree-of-freedom rotorcraft test bed demonstrates the essential features of system and trajectory modeling, maneuver example selection, maneuver class synthesis, and integration into a hybrid system path planner.
Nomenclature= goal-attainment binary variable b man = maneuver class binary variable C c, j = time duration constant for maneuver class j C s, j = time duration matrix for maneuver class j c i = vehicle model coefficientsmaneuver class duration state D x = differentiation operator with respect to variable x d i = vehicle model coefficients e = data matching error metric F = nonlinear equation set f = nonlinear program objective functioñ f = continuous-time dynamic consistency function g = inequality constraint vector H = planning decision horizon . ¶ Principal Member, Technical Staff, 555 Technology Square; mcconley@draper.com. h = equality constraint vector h bc = boundary condition equality constraint vector h 0 bc = boundary condition equality constraints invariant with α h em = dynamic consistency equality constraint vector h em = continuous-time dynamic consistency function i = summation index J = planning objective function J i = active constraint set i j = summation index k = spline order; planning decision step k i = affine maneuver design constants for planning l = summation index = linear constraint M c, j = state transition vector for maneuver class j M s, j = state transition matrix for maneuver class j M = vector of large numbers m j = binary variable for maneuver class j N = number of data samples N f = number of final condition maneuver parameters N i = number of initial condition maneuver parameters n v = number of spline coefficients for signal v p = finite-dimensional trajectory parametrization S e = sampling of unit interval for equality constraints S g = sampling of unit interval for inequality constraints s = arc length in v-space s i = ith sampling point T = maneuver duration T s = linear-time invariant (LTI)-mode discretization interval t = time u = direct difference vector u = projected feasible difference vector...