HAMR : Low-Cost Holonomic Mobile Robot
Senior Design Project at UPenn
Fall 2015 - Spring 2016
My interdisciplinary senior design team at of four designed, built and characterized an affordable holonomic wheeled mobile robot (WMR) platform based on a novel drive mechanism that lowers the cost barrier for research in telepresence robots, mobile manipulators, and humanoid robots.
HAMR (the Holonomic Affordable Multi-Terrain Robot) is based on a unique drive system consisting of a differential-drive base with an offset turret mounted on top, which can be intuited as a swivel caster where all three degrees-of-freedom (DOF) are actuated. This drive mechanism is less expensive and more durable than omni-wheels or powered-casters.
SWIVEL CASTER DOF
HAMR DOF
I was the project lead and was in charge of mechanical design, manufacturing, and logistics. I created a novel metric for WMR mobility, “holonomicity,” and developed an extension of a tool used to characterize robotic arms (the manipulability ellipse) adapted to characterize mobility, the mobility ellipse (ME). I used the ME to optimize HAMR’s geometry for holonomicity.
HAMR COORDINATE FRAMES
HAMR MOBILITY ELLIPSE
HAMR is capable of traversing ADA compliant terrain (thresholds, floor gaps, etc) at a maximum payload of 65 lbs. HAMR’s controller uses feedback from quadrature encoders and an on-board gyroscope to enable precise motion control.
We won Third Place in the UPenn Engineering Senior Design Competition, received the William K. Gemill Memorial Prize for Outstanding Creativity, and were finalists in the Intel-Cornell Cup. My research on holonomicity provided the basis for a paper accepted to the proceedings of the 2017 IEEE International Conference of Robotics and Automation. This project has evolved into the holonomic mobile base for Quori, a socially interactive robotic platform currently in development at UPenn’s ModLab (PI: Mark Yim).
