A Computerized Dynamic Synthesis Method for Generating Human Aerial Movements

A computerized method based on optimal dynamic synthesis was developed for generating the flight phase of somersaults. A virtual gymnast is modeled as a planar seven-segment multibody system with six internal degrees of freedom. The aerial movement is generated using a parametric optimization technique. The performance criterion to be minimized is the integral quadratic norm of the torque generators. The method produces realistic movements showing that somersaults perfectly piked or tucked appear spontaneously according to the value of the rotation potential of the initial movement. It provides accurate knowledge of the evolution of joint actuating torques controlling the somersault, and makes it possible to investigate precisely the configurational changes induced by modifications of the rotation potential. Four simulations are presented: one with a reference value for the rotation potential, two with reduced values, and the last with a different hip flexion limit. They give an insight into the coordination strategies which make the movement feasible when the rotation potential is decreased. The method gives accurate assessments of the energetic performance required, together with precise evaluations of the mechanical efforts to be produced for generating the acrobatic movement.