How is sensory feedback used to tune elastic systems?

Cane toads use elastic elements in their forelimbs as brakes to absorb impacts during landing.   In collaboration with Gary Gillis, I’ve been exploring how anurans integrate sensory information to tune elastic elements essential to coordinated landing.  To do this, we’ve performed several experiments to conflict or ablate sensory information and evaluated the influence on landing preparation.

 

Here we  were testing whether toads prepare each forelimb for landing individually by having them land with one limb before the other and measuring muscle timing and activity levels.

Using wearable robotics to uncover how organisms control elastic systems

Robobird:  In collaboration with Jonas Rubenson and Greg Sawicki, I have built a lower limb orthosis for a guinea fowl. We’re exploring the musculoskeletal and neural adaptations to wearable robotics and trying to understand  the sensory feedback mechanisms by which animals adapt to their use.  Here the exoskeleton is a tool to systematically perturb the system to help us discern the rules the body uses to tune elastic systems to different environmental conditions.

Musculoskeletal modeling to understand complex elastic systems

A musculoskeletal model allows us to explore complex dynamics that result from the interaction of many many elastic elements.  We’ve developed a OpenSim lower limb model of the guinea fowl that can integrate our exoskeleton and be constrained by experimentally collected muscle activation, length or tendon force data.  This allows us to estimate the excitation patterns of all muscles in the lower limb in response to an exoskeleton perturbation, providing a data rich window into how an animal coordinates the control of many elastic elements working in concert.

OpenSim Guinea fowl model driven by experimentally collected kinematic and kinetic data