Author: sponberg
Multiscale Physics of Muscle
Flight in unsteady flows
Centralization of Locomotor Control in Roaches & Robots
Animals such as cockroaches must coordinate the movements of multiple legs, which are coupled components of a complex hybrid-dynamical system, in order to stably run. Coordination could be achieved through a decentralized control architecture, where a motor command for a particular muscle is only informative of the variation of the local states of the limb, […]
Moths change their behavior, but not their aerodynamics to feed in windy environments
Hawkmoths naturally hover and feed from flowers in nature. Insects have developed an assortment of unsteady aerodynamic mechanisms to generate the high-lift necessary for hovering. While feeding, hawkmoths rely on precise wing kinematics to not only remain aloft, but also track the motion of flowers as they sway in the wind. Previous work revealed that […]
X-ray diffraction through living muscle
How does the action of millions of molecular motors enable muscle, nature’s most versatile material, to power movement?One of the features that makes muscle so unique is the exquisite organization of millions of molecular motors into a highly regular protein lattice. Muscles contract via the interaction of many parallel protein fibers (actin & myosin) that […]
Moths slow their brains to track flowers in low light
Hawkmoths, like Manduca sexta, hover and track moving flowers during natural foraging in low light environments. Neural recordings from the visual part of the moth’s brain have suggested that as light levels drop, the moth changes its sensitivity to light by integrating light for a longer period of time. Such a strategy raises the possibility […]
How antennae encode mechanical stimuli for tactile navigation
In an earlier research project with Dr. Jean-Michel Mongeau (now professor at PSU) we looked at the how cockroaches use their antennae as to feel surface in front of them and navigate in low light. Our approach in that project was to find the simplest control law the cockroaches could be using to maneuver by […]
Simultaneous dimensionality reduction of motor commands and movement
Once a behaving organism has acquired, processed, and transmitted sensory information it must still alter patterns of motor activation in a manner that enables control. A central challenge in understanding motor control, particularly during complex rhythmic behaviors like flight, is decoding the specific features of body dynamics that are control by patterns of neural feedback […]
Control theoretic approaches to experiment and analysis of locomotion
Locomotion is an inherently closed-loop process. What that means is that when we move it changes how we perceive the world — turning to your left is like the world around you rotating to the right. As a result, what we see (or sense) is the difference between how an object in our world is […]