(Georgia Institute of Technology, 2012-10-26)
Aguilar, Jeffrey; Lesov, Alex; Wiesenfeld, Kurt; Goldman, Daniel I.
We study vertical jumping in a simple robot comprising an actuated mass-spring arrangement. The actuator frequency and phase are systematically varied to find optimal performance. Optimal jumps occur above and below (but not at) the robot’s resonant frequency f0. Two distinct jumping modes emerge: a simple jump, which is optimal above f0, is achievable with a squat maneuver, and a peculiar stutter jump, which is optimal below f0, is generated with a countermovement. A simple dynamical model reveals how optimal lift-off results from nonresonant transient dynamics.
(Georgia Institute of Technology, 2012-10-25)
Wiesenfeld, Kurt
Rhythms abound in the natural world. Spontaneous rhythmic coordination can be essential: our beating heart cells must synchronize precisely – or else! Sometimes, too much coordination is disastrous: brain seizures can occur as a result of abnormally high levels of synchronous neuronal activity. Examples of spontaneous synchronization are found in every branch of science, from the beautiful nightly light shows of firefly swarms to the synchronized swinging of pendulum clocks. Researchers the world over are trying to understand how coordinated rhythms arise and trying to discover ways to control them. An array of applications awaits: faster computers, brighter lasers, collision avoiding cars; new strategies for treating heart and brain disorders; even an end to the devastation of periodic locust swarms.