tailieunhanh - Electrical Engineering Mechanical Systems Design Handbook Dorf CRC Press 2002819s_19

Tham khảo tài liệu 'electrical engineering mechanical systems design handbook dorf crc press 2002819s_19', kỹ thuật - công nghệ, điện - điện tử phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | the single ones . For the sake of simplicity let us consider the rigid body model that is a relatively good approximation of the humanoid dynamics though it represents a very idealized model of the human gait. The multi-DOF structures of the human locomotion mechanism joint flexibility and structural and behavioral complexity of the foot support the realization of dynamic gait patterns that are difficult to achieve with the existing humanoid systems. During locomotion the following active motion forces act on the body links Gi Gravitation force of the i-th link acting at the mass center Cị F Inertial force of the i-th link acting at the mass center Ci M Moment of the inertial force of the i-th link for Ci i i R Resultant ground reaction force All active motion forces gravitational and inertial forces and moments can be replaced by main resultant gravitation and inertial force and in most cases resultant inertial moment reduced at body center of mass CoM . The ground reaction force and moment can be decomposed into vertical and horizontal components with respect to the reference frame. The horizontal reaction force represents the friction force essential for preserving the contact between the foot and the ground. The vertical reaction moment represents the moment of the friction reaction forces reduced at an arbitrary point P. We will assume a stable foot-floor contact without sliding. This means that the static friction forces compensate for the corresponding dynamic body reaction forces. Accordingly the vertical reaction force and horizontal reaction moment components represent the dynamic reaction forces that are not compensated by the friction. The decomposition will be presented in the following form r r r R R Rf v f M rM. M. h f where the indices h and v denote the horizontal and vertical components respectively while f indicates the friction reaction force and moment components. Let us select the ZMP as the reduction point of interest . P ZMP. Then .