The effect of friction on the vibro-impact locomotion system: modeling and dynamic response

This paper shows a new study on the effect of various dry and isotropic friction levels on the progression and dynamic response of a vibro-impact locomotion system. An experimental vibro-impact self-propelled apparatus, which is able to vary the friction force while remaining the total weight of the system, was practically implemented. A new dimensionless model was developed based on the validated mathematical model, allowing to examine the effects of the excitation force and the friction force independently. The experimental data revealed that, the force ratio between the excitation magnitude and friction level would not be totally correct to represent the excitation effects in dimensionless modeling the system. The level of friction force may have a significant effect not only on how fast the system move, but also on which direction of the progression. Bifurcation analysis and basin of attraction were calculated to scrutinize the effect of friction on the scaled model. The results showed that various friction would lead to either period-1 or chaotic motion of the system. The new findings would be useful for further studies on the design and operation of vibro-impact driven locomotion systems and capsule robots.