Neuromechanical models for insect locomotion: Stability, maneuverability, and proprioceptive feedback.
We describe a hierarchy of models for legged locomotion, emphasizing relationships among feedforward (preflexive) stability, maneuverability, and reflexive feedback. We focus on a hexapedal geometry representative of insect locomotion in the ground plane that includes a neural central pattern generator circuit, nonlinear muscles, and a representative proprioceptive sensory pathway. Although these components of the model are rather complex, neglect of leg mass yields a neuromechanical system with only three degrees of freedom, and numerical simulations coupled with a Poincaré map analysis shows that the feedforward dynamics is strongly stable, apart from one relatively slow mode and a neutral mode in body yaw angle. These modes moderate high frequency perturbations, producing slow heading changes that can be corrected by a stride-to-stride steering strategy. We show that the model's response to a lateral impulsive perturbation closely matches that of a cockroach subject to a similar impulse. We also describe preliminary studies of proprioceptive leg force feedback, showing how a reflexive pathway can reinforce the preflexive stability inherent in the system.
Kukillaya
R
R
Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, USA.
Proctor
J
J
Holmes
P
P
D000818:Animals; D001696:Biomechanical Phenomena; D003058:Cockroaches / Q000502:physiology; D005121:Extremities / Q000502:physiology; D007313:Insecta / Q000502:physiology*; D008124:Locomotion / Q000502:physiology*; D008954:Models, Biological; D008959:Models, Neurological; D017711:Nonlinear Dynamics; D011434:Proprioception / Q000502:physiology