Comprehensive Research On Dynamics Motion Of Hopping Kangaroo Mechanical Systems

Bionic mechanical systems can adapt to environment of the future world that is unstructured and unknown, and they can lead the trend of the future robotics. One-legged bionic robot is an important branch of bionic mechanical systems which have strong capacity to adapt to the environment.In the paper, the research development of hopping robot is summarized, and the main issue of the paper is illustrated.On the basis of dynamic synthesis, a novel elastic underactuated mechanism is proposed. The proposed hopping robot is a non-SLIP model system, which generally shows more biological characteristics. Then, mathematical model of the system is established according to Lagrange method, Kinetic-energy theorem and Momentum theorem etc.Thanks to the special design, it is proved that the dynamics of the presented hopping robot mechanism can be transformed into the strict feedback normal form. Then a sliding model backstepping control is proposed and proved for stabilizing the nonlinear dynamic system in stance phase.Based on the above, this paper proposes a complete set of numerical algorithms for periodic motion planning of the hybrid nonlinear dynamic systems. As effectiveness of the algorithm is influenced by the initial state of the motion, optimization algorithm for the initial state based on Genetic Algorithm (GA) is used in the first, and the optimal initial state of periodic motion is searched by taking minimum energy-loss as objective. Secondly, dynamic equations are converted to algebraic equations by Poincare Section method. At last, search algorithm of fixed point based on Newton-Raphson Algorithm is used to search the hybrid nonlinear dynamics periodic trajectory, and the fixed point of Poincare Section is searched to search Limit Cycles of the system about passive periodic motion.In the last part of the research, we present a theoretical study of the self-excited hopping of a hopping mechanism. From the parameter study, it was found that stable hopping locomotion is possible over a wide range of feedback gain and link parameter values and that the walking period is almost independent of the feedback gain. The numerical algorithm is applied to research on dynamics motion of the one-legged bionic robot. The paper has obtained Poincare Section’s fixed point by solving equation and realized dynamics periodic motion planning that greatly improves the energy efficiency of movement about the system, and the result may be direct reference for designing related controller.