APS -APS March Meeting 2017 - Event - Coordinated Body Bending Improves Performance of a Salamander-like Robot

摘要

Analyzing body morphology and limb-body coordination in animals that can both swim and walk is important to understand the evolutionary transition from an aquatic to a terrestrial environment. Based on previous salamander experiments (a modern analog to early tetrapods and performed by Hutchinson's group at RVC in the UK) we built a robophysical model of a salamander and tested its performance on yielding granular media (GM) of poppy seeds. Our servo-driven robot (405 g, 38 cm long) has four limbs, a flexible body, and an active tail. Each limb has two servo motors to control up/down and fore/aft positions of limb. A joint in the middle of the body controls horizontal bending. We assessed performance of the robot by changing the body bending limit from $0^{circ}$to $90^{circ}$and measured body displacement and power consumption over a few limb cycles at $0^{circ}$and $10^{circ}$sandy slope. We fixed the angle of the legs according to body to test the effect of body bending directly. On GM, step length increased from 0 to 9.5 cm at $0^{circ}$ and 0 to 7 cm at $10^{circ}$slope while the average power consumption increased $50% $. A geometric mechanics model revealed that on level GM body bending was most beneficial when phase offset $180^{circ}$from leg movements; increasing the maximum body angular bend from $45^{circ}$to $90^{circ}$ led to step length increases of up to $90% $.