INTRODUCTION: One aim of the snowboard dynamic Simulation is the optimization of the snowboarder movement in order to obtain a preset trajectory on the slope moving the board äs fast äs possible and to chose, among those available, the board with the more suitable mechanical characteristics. This preliminary work is mainly focused on the model of board-snow contact and on the development of a robust control system capable of maintaining the board on a given trajectory, METHOD: By mean of an appositely designed apparatus, by a statte simplified model or by an approximate geometrical relationship, it is possible to relate the turning radlus with the Position and the edging of the board on the slope. Thus, considering pure carving, a multibody model of board and snow-boarder can be simply driven by the edging angie. All the nominal lateral edge of the board is supposed in contact with the snow. For the board-snow a "tire-like" contact model have been used, contact force components are: Fz = min (0.0, {F2|c + Fzc}); Fx = -CSLIP x ss ;Fy = - U * |F2|x (1-H3) x sign(Alpha). The snow stiffness and damping are included in the contact model (Fzk + FZC)- Friction forces between board and snow are related to the board angle of drift. The model parameters have been optimized in orderte reproduce the turn äs previously calculated. The control will drive the board by means of the body movements, but the preliminary model of the snowboarder have a rigid posture and is fixed to the board, thus, at present, the control generates fictitious actions {forces and couptes) acting on the System in order to maintam the edging required to follow the given trajectory. RESULTS: Control robustness has been positively checked under various perturbation and control gains have been tuned by means of many numerical Simulation. DISCUSSION: The control is capable to keep ihe board in the desired position and by means of the contact model can replicate the preset trajectories. The same effect obtained, at present by the fictitious control actäons on the Systems will be obtained at next step by controlling the snowboarder motion. In both cases all the internal actions transmitted by the components of the system can be continuously monitored. CONCLUSION: The control method described can 'ride' the snowboard on a slope. This is the first step to understand snowboarding dynamics and to optimize the contact model, next one will be focused on rider motion: contra) movements wül be compared to joints laws of motion acquired on the fleld in order to evaluate the efficacy of specific driving techniques.
© Copyright 2007 4th International Congress on Science and Skiing. Julkaistu Tekijä University of Salzburg. Kaikki oikeudet pidätetään. / Kääntänyt https://www.DeepL.com/Translator