Modeling, analysis, and experiments of a pause-and-leap jumping robot during takeoff, flight, and landing buffering

Jumping robots can overcome obstacles strongly and are suitable for complex terrain environments. However, the takeoff parameters of most jumping robots, especially pause-and-leap jumping robots, cannot be changed accurately. Moreover, the stability of the flight and landing of these robots needs to be improved. On the basis of observations of the jumping process of a locust, leg mechanisms, including one-degree-of-freedom jumping leg and series buffering leg, are designed. Then, dynamic models for takeoff, flight, and landing buffering are established and combined with Lagrange/Newton-Euler dynamic modeling methods and conservation of momentum moment. For the former, the effects of structural parameters, including position of the driving spring, absolute position of the center of mass, and stiffness coefficient of the driving spring, on takeoff velocity and acceleration can be obtained. The takeoff parameters can also be changed accurately. For the flight phase, the relationship between the relative position of the center of mass and the stability of flight is revealed. For the latter, the effects of two buffering modes on the supporting forces and energy storage capacity are analyzed. On the basis of the parameters determined by the abovementioned modeling method, a prototype is developed, and an experiment is conducted to verify the rationality of the modeling method. Experimental results show that the prototype can acquire accurate takeoff parameters and achieve stable flight and landing buffering. This study provides a useful reference for the design and control of jumping robots.