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From LIMBS

Antenna-based wall following

Myriad creatures rely on compliant tactile arrays for locomotion control, mapping, obstacle avoidance and object recognition. Our laboratory is "reverse engineering" the neural controller for cockroach wall following to better understand sensorimotor integration in nature. In addition, we are building tactile sensors, inspired by their biological analogs.

Task-Level Control of Wall Following in Cockroaches

The American cockroach, Periplaneta americana, is reported to follow walls at up to 25 turns/s. During high-speed wall following, a cockroach holds its antenna relatively still at the base while the flagellum bends in response to upcoming protrusions. We developed a simple mechanosensory model for the task-level dynamics of wall following. In the model a torsional, mass-damper system describes the cockroach’s turning dynamics, and a simplified antenna measures distance from the cockroach’s centerline to a wall. Nyquist and root-locus analyses predict that stabilizing neural feedback requires both proportional feedback (difference between the actual and desired distance to wall) and derivative feedback (velocity of wall convergence) information from the antenna. For more information, see [CLF06].

Antenna-based Control of the Lateral Leg Spring (LLS) Model of Cockroach Locomotion

The Lateral Leg Spring (LLS) model was developed by Schmitt and Holmes to model the horizontal-plane dynamics of a running cockroach. The model captures several salient features of real insect locomotion, and demonstrates that horizontal plane locomotion can be passively stabilized by a well-tuned mechanical system, thus requiring minimal neural reflexes. We treat the LLS as a “plant model” and biologically inspired control law that enables the model to follow along a virtual wall, much like antenna-based wall following in cockroaches. For more information, see [LSLLFC08], [LLSC06].

Biologically-Inspired Tactile Sensing

Like their biological analogs, robotic tactile sensors should enable their host to negotiate cluttered environments in low light. These multifunctional, light weight, low power, "quiet" sensors complement existing proximity sensors, particularly in low-light, tight spaces with highly polished surfaces and high air- or water-particle content, where modalities such as infrared, sonar, vision and lasers fail. Through a sequence of undergraduate student and high-school student projects, we are developing novel tactile sensors for high-speed robotic wall following. For more information, see [LLKC05], [LSLLFC08].