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DOI: 10.1177/0278364904047393 Optimal Gait Synthesis of a Seven-Link Planar BipedLaboratoire de Mécanique des Solides, CNRS-UMR6610, University of Poitiers, SP2MI, Bd. M. & P. Curie, BP 30179, 86962 Futuroscope-Chasseneuil, France, bessonnet{at}lms.univ-poitiers.fr
Laboratoire de Mécanique des Solides, CNRS-UMR6610, University of Poitiers, SP2MI, Bd. M. & P. Curie, BP 30179, 86962 Futuroscope-Chasseneuil, France
Laboratoire de Mécanique des Solides, CNRS-UMR6610, University of Poitiers, SP2MI, Bd. M. & P. Curie, BP 30179, 86962 Futuroscope-Chasseneuil, France In this paper, we carry out the dynamics-based optimization of sagittal gait cycles of a planar seven-link biped using the Pontryagin maximum principle. Special attention is devoted to the double-support phase of the gait, during which the movement is subjected to severe limiting conditions. In particular, due to the fact that the biped moves as a closed kinematic chain, overactuation must be compatible with double, non-sliding unilateral contacts with the supporting ground. The closed chain is considered as open at front foot level. A full set of joint coordinates is introduced to formulate a complete Hamiltonian dynamic model of the biped. Contact forces at the front foot are considered as additional control variables of the stated optimal control problem. This is restated as a state-unconstrained optimization problem which is finally recast, using the Pontryagin maximum principle, as a two-point boundary value problem. This final problem is solved using a standard computing code. A gait sequence, comprising starting, cyclic, and stopping steps, is generated in the form of a numerical simulation.
Key Words: sagittal gait gait optimization Pontryagin maximum principle
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