Collision-based energetic comparison of rolling and hopping over obstacles

Area of Science:

• Robotics
• Biomechanics
• Mechanical Engineering

Background:

• Ground-machine interactions significantly affect robot locomotion in rough terrain.
• Obstacle interaction involves energy losses comparable to hopping and walking.

Purpose of the Study:

• To investigate and compare the energetic costs of overcoming obstacles for rolling versus hopping locomotion.
• To analyze the influence of moment of inertia and Froude number on locomotion efficiency.

Main Methods:

• A simple mechanics model was developed, focusing on collision-based interactions without friction.
• Energetic costs were quantified and analyzed for rolling and hopping strategies.
• Allometric scaling laws were applied to compare model results with animal locomotion data.

Main Results:

• Hopping locomotion is energetically advantageous over rolling at higher Froude numbers, while rolling is superior at lower Froude numbers.
• The transition speed where hopping becomes more efficient aligns with observed animal gait transition speeds.
• Model predictions for energetic collision losses were experimentally validated.

Conclusions:

• The energetic efficiency of different locomotion strategies is dependent on system parameters like Froude number and moment of inertia.
• The findings provide insights into the design of efficient robots for rough terrain and offer a comparative perspective with animal locomotion.
• The study validates the use of simple mechanical models for predicting energy losses in locomotion.