One Foot Hopping Robot Dynamics Analysis And Design Study

At present bio-robot research mainly concentrated in the wheel (tracked) robot and crawling robot. Compared with these robots, hopping robots can leap relatively large obstacles to locomote on the more complex terrain. In the first part the research development of hopping robot is summarized, and the main issue of the paper is illustrated.After summarizing the limitations of existing one-legged hopping robots, a new model of one-legged hopping robot is proposed. This new hopping robot is actuated by two arms, and includes an elastic, telescopic, unactuated leg. Such motions of the one-legged robot as balancing in dynamic stance, lifting off, hopping continuously are accomplished by the coupling of the dynamic of the system. For this kind of underactuted dynamic system, the dynamics models in the stance and flight phases are founded. The correctness of the model is verified by simulations in Matlab, which serves as a theoretical foundation for the motion control and structure optimization of the robot.Analysed the dynamic models, we established math optimization model aimed at improving the coupling capability of the robot. After the optimization problem is calculated in Matlab optimization toolbox, the mechanical structure of robot is designed , together with a locomotion-assistant crane.Based on dynamic model of the one-legged hopping robot, the dynamic coupling indices were defined with influence coefficient concept. The optimal configurations of two actuated arms were calculated for each dynamic coupling index. Three important motion task of the system were simulated in Matlab, the results show that the dynamic coupling analysis are correct. Based on the dynamic coupling analysis and the study on simulation results, motion planning of initial configurations and equilibrium points of two arms were studied for three motion task. After motion planning, the motor output torque of two actuated arms were minimum.The differential flatness characteristic is discussed in the paper, and a method of transform the system model to a differential flatness system by approximating system variables is analysed. The feasible locomotion curve achieved by value-insert mathematic method also provide a theoretical warrant for the research of motion control algorithm.At the last part of the paper, the whole experiment system is introduced, the issue emerged in balance experiment is analysed, and the advice of improve the mechanical structure of hopping robot is presented.