Abstract: In order to understand how elasticity works on reducing energy dissipation and improving locomotion efficiency of hopping robots, the passive hopping behaviors of hopping robot models with rigidly or elastically suspended load are examined. The influence of different system parameters on energy dissipation is discussed. Theoretical analysis and simulation results show that hopping robots with elastically suspended load exhibit lower energy dissipation than those with rigidly suspended load, because part of the kinematic energy is stored in the suspension spring during the stance phase. As the suspension damping increases, higher stiffness will be needed for the suspension spring to minimize the energy dissipation during hopping. During the flight phase, hopping robots with dissipative elastic suspension have energy dissipation which is, however, much smaller than that during the stance phase, therefore the effect of energy dissipation reduction will not be affected.

Key words: automatic control technology, elasticity, hopping robot, energy dissipation, energy transfer