#### Welcome

Professor Revzen and his team at the Biologically Inspired Robotics and Dynamical Systems (BIRDS) Lab are working on discovering, modeling, and reproducing the strategies animals use when interacting with physical objects. This work consists of collaboration with biomechanists to analyze experimental data, developing new mathematical tools for modeling and estimation of model parameters, and construction of robots which employ the new principles.

#### Suggested Reading

##### The Twisting Tennis Racket

This paper describes, analyzes, and explains a novel twisting phenomenon which occurs in a triaxial rigid body (such as a tennis racket) when it is rotating ...

##### Event Triggered Stablization

Event-triggered control is an idea that appears pleasing theoretically, as well as relaxes the need to have periodic signalling - robotics, it would reduce c...

##### A direct method for Trajectory Optimization of Rigid Bodies Through Contact

A paper about trajectory optimization in hybrid systems. Interesting, as it relaxes would be naively been consider a core constraint of hybrid systems - the ...

##### Optimization-based Locomotion Planning, Estimation, and Control Design for Atlas Humonoid Robot

A fun paper expanding on the control methods used in the well-known and well-performing Atlas robots by Boston Dynamics. A little bit of a 'behind the curtai...

##### Sensory Feedback in Cockroach Locomotion - Current Knowledge and Open Questions

The American cockroach, Periplaneta americana, provides a successful model for the study of legged locomotion. Sensory regulation and the relative importance...

##### Snake-Like Robots

Limbless organisms such as snakes can navigate nearly all terrain. In particular, desert-dwelling sidewinder rattlesnakes (Crotalus cerastes) operate effecti...

#### Recent News

##### A nice proof of Grönwall's inequality

Here is a nice proof of Grönwall's inequality.

##### Affine Nonholonomic Systems

Lagrangian mechanics is an important tool to understanding mechanical systems, but often must incoporate nonholonomic constraints. When the constraints are a...

##### Differentiation under the integral sign

In calculus, Leibniz's rule for differentiation under the integral sign states that, modulo precise regularity assumptions, $$\frac{d}{dx} \int_{a(x)}^{b(x)}...

##### A fun fact about the Euler characteristic

There are many equivalent definitions of the Euler characteristic $\chi(Y)$ of a space $Y$. I recently learned another of these, valid in the case that $Y$ i...

##### Rigorous Enclosures of a Slow Manifold

Slow-fast dynamical systems have two time scales and an explicit parameter representing the ratio of these time scales. Locally invariant slow manifolds alon...

##### Bifurcation and chaos in the simple passive dynamic walking model with upper body

We present some rich new complex gaits in the simple walking model with upper body by Wisse et al. We first show that the stable gait found by Wisse et al. m...