The Research On The Trajectory Planning Of Joint Space And The Jumping Characteristics Of One Legged Hopping Robot

Legged robot which has jump function is adapt to the complex unstructured environment in nature to a great extent, whose advantages are more obvious in the space exploration of low gravity. Therefore, the study of legged hopping robot is necessary. This dissertation concentrates on one leg hopping robot with foot, and the kinematics and dynamics models are established, with the jumping process constraints analyzed. The trajectory planning of whole jump process in joint space is studied,analyzing some hopping characteristics, and the experiment is performed.Based on the physiological analysis of kangaroo and human leg, the main factors which impact jumping movement are summarized,and the principium model of jumping structure is ed, and jumping mechanism is analyzed. The structural design criteria is determined,and finally specific structure of physical prototype is designed.For the legged hopping robot with foot, the movement action of the whole jumping process is analyzed, including stance phase, underactuaed phase, flight phase and land phase.The global and local coordinate system, the generalized coordinates, and the structural parameters are set on the mechanism model of hopping robot. The kinematic and dynamic model of the legged robot in the whole process is built respectively through D-H method and Lagrange method.The trajectory planning method based on the principle of minimum energy in joint space is proposed to resolve the underactuation of foot. Based on the comprehensive analysis of the whole process constraints, the design variables, objective function, optimization algorithm and optimization steps are determined. Trajectory in joint space is simulated by MATLAB with real model parameters, obtaining the kinematic characteristic curves and dynamic characteristic curves.Based on unique jump features of hopping robot, the jump stability,dynamics,dexterity are analyzed respectively. The ground reaction force, ZMP (zero moment point) and angular momentum around the center of mass are studied studying the effects of foot rotation on jump performance. The dynamics coupling characteristics of underactuaed joint are analyzed and the common indicators of dexterity and manipulability are proposed based on the direction of centroid movement.The robot system is simulated by MATLAB, and the specific controller is designed,finally hopping experimental are implemented. The experimental result shows that: the jump indicators of experiment are basically realized, and the applicability of trajectory planning method based on the principle of minimum energy consumption is verified to be suit and correct for legged hopping robot with foot.The research achievements have certain reference value in the research on the trajectory planning of joint space of legged hopping robot with foot.