Projects

Summary

Trajectory generation techniques are a core enabling technology in any planning or control framework. The need for these techniques to compute rich libraries of motions has even greater importance as underactuated hybrid dynamical systems such as legged robots and unmanned aerial vehicles are put into service. When computing trajectories for these types of systems, most state-of-the-art approaches rely on randomly guessing seed values or the user acquiring model-specific knowledge in order to find desired trajectories in the system’s trajectory space. These strategies have diminishing returns as operational needs or the models change.  With a greater drive towards autonomy, the objective of this research is to develop new concepts, theory, and algorithms for computing trajectories of underactuated hybrid dynamical systems without resorting to random guessing.

Summary

A challenging problem in bipedal locomotion is given an underactuated biped robot, design a stable walking gait. There are many notions of stability in the bipedal walking literature (e.g., eigenvalues of the linearized system, zero moment point, capturability, etc.), but the general idea is the same: if the given criteria is satisfied, the robot will not fall down.

While the theory behind how these approaches propose not to fall down can often be proven mathematically, there still remains open problems in finding a single stable gait and its extension to creating a library of stable gaits. The goal of this project is to propose a framework for computing a library of stable gaits for general biped robots.

As a first step towards this goal, we aim to design, assemble, and control a limit-cycle walker.  The design parameters are to make it a low-cost mini bipedal robot capable of maintaining a steady walking gait.

Summary

For autonomous wheeled robots, the size of traditional cylindrical wheels (TWs) limits a wheeled robot’s ability to navigate challenging terrain such as forests, mountains and swamps. This lack of mobility impacts a wide range of applications where wheeled robots have advantages over other modes of locomotion, like legged locomotion. For example, vital tasks such as search and rescue in collapsed infrastructure, planetary exploration on Mars, and transportation of goods and people on unpaved roads are, in part, limited by the choice of geometry used for wheeled vehicles in difficult terrain. The application of omnidirectional ball wheels (OBWs) in robotics introduces a different approach to off-road mobility due to utilizing spherical tires compared to the traditional cylindrical tires for wheels. Despite there being research on OBWs, this research proposal investigates the effects of a wheel's geometry on increasing a wheeled robot’s mobility in challenging environments rather than flat surfaces.

Summary

In this project, we aim to exploit the natural dynamics of an eccentrically loaded hopping hoop in order to create an underactuated jumping robot without the traditional use of springy legs. The design objective is to create an underactuated ball-shaped robot that can roll, slide, and jump.  The primary actuator is a motorized pendulum, which replaces the need for legs in a hopping robot design. The project explores the possibilities of unconventional motion mechanisms in robotics, specifically underactuated systems.