Dynamic Robotics Lab

In the Dynamic Robotics Laboratory located in Corvallis, OR I worked to understand the dynamics of running and walking. While many have worked to build running and walking robots in the past, the great minds in the lab feft that the fundamentals of these tasks were still not fully understood. We worked closely with our collaborators at the University of Michigan, Carnegie Melon University as well as biologists and biomechanists across the pond to build, test, and better understand biologically inspired running robots.

Below are some pictures of the second iteration of what we believed was the proper way to build a robot capable of robustly running and walking. We call it ATRIAS 1.0 which stands for Assume The Robot Is A Sphere. While a running joke in the mathematics and physics world where people like to assume complex systems are simply represented as a sphere to make the math easier, we have worked to develop this particular robot to be as simple as possible to control.

The main feature of this robotic system is the implementation of compliance into the actuation system known as a series elastic actuator or SEA. This series compliance allows us to decouple the inertias of the motors from the impacts in the ground. This gives us the ability to store much of the energy that is usually lost by conventional robots when they hit the ground. Instead of stopping the entire robot instantly, the springs deflect and store a large amount of energy to be released on the next hop.

Once ATRIAS 1.0 was built we began designing a new version 2.0. The goal of 2.0 is to help eliminate some of the physical limitations and assembly issues of the first version. The cable drive mechanisms have been replaced by a harmonic drive which gives us the large gear reduction needed to supply the right amount of torque to the springs to drive the legs. The entire motor and transmission system has also been optimized by keeping it symmetric to help with assembly and cost. The new assembly is much more elegant and will prove to be far superior to ATRIAS 1.0. Here are some photos of the SolidWorks models of the new system. The first image is of just a monopod version. Secondly, the system will be assembled with a torso and another leg to create a bipedal runner. The last image is showing the complexities of the drive system. We have designed the custom motor enclosures and gear systems.