Bio-inspired Antennal Tactile Sensing
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Date
2015-02-09
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Johns Hopkins University
Abstract
Vision dominates perception research in robotics and biology, but for many animals, it is not the dominant sensory system. Indeed, arthropods often rely on sensory cues sampled via a pair of passive head-mounted antennae to achieve navigation and control. These mechanosensory structures support multimodal receptors—tactile, hygrometric, thermal, olfactory—enabling a wide range of sensorimotor behaviors.
One model biological system, Periplaneta americana cockroach, performs a remarkably robust escape behavior by using its long, slender, flexible antennae to facilitate rapid closed-loop course control. The antenna is a passive, hyper-redundant kinematic linkage that acts as a distributed tactile sensory structure to mediate mechanical interactions with the environment at very high rates. This thesis demonstrates that the antennal mechanics are tuned to enable high-speed, high-bandwidth locomotor control even in total darkness.
Despite the extraordinary success of antennal sensing in nature, there are few effective bio-inspired antennae. To incorporate similar antennal sensing capability in agile mobile robots, I developed a tunable bio-inspired modular robotic research antenna and experimentation platform. I also synthesized numerical models to approximate antenna mechanics under relevant boundary conditions, which I verified against my physical model. Both numerical simulations and physical experiments were conducted to isolate fundamental parameters that underly the stability and performance I observed in the biological model.
Using a combination of numerical and robotic experiments, in concert with biological experiments conducted by my collaborators, I discovered that several behaviorally relevant characteristics of an antennae are predominantly governed by a combination of (1) the stiffness profile of the antenna and (2) the interaction of hairlike mechano-structures along the length of the antenna. I found that the “right” combination of these features improves the postural stability and the steady state spatial acuity of tactile interaction with the environment. Specifically, antennae with an exponentially decreasing stiffness profile accompanied by distally pointing anisotropic mechano-hairs are ideal for navigation tasks, and greatly facilitate stable high-speed
wall following.
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Keywords
tactile sensing, distributive sensing, cockroach locomotion, antennal sensing, touch sensing, passive mechanics, periplaneta americana, bio-inspired robotics, high-speed wall-following, thigmotaxis