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  • CS Colloquium: Jonathan Kelly (University of Toronto) - Keeping Your Distances: A Distance-Geometric Perspective on Inverse Kinematics

    Tue, Oct 04, 2022 @ 03:30 PM - 04:50 PM

    Thomas Lord Department of Computer Science

    Conferences, Lectures, & Seminars

    Speaker: Jonathan Kelly, University of Toronto

    Talk Title: Keeping Your Distances: A Distance-Geometric Perspective on Inverse Kinematics

    Series: Computer Science Colloquium

    Abstract: In this talk, I will discuss recent work in my group on the problem of inverse kinematics (IK): finding joint angles that achieve a desired robot manipulator end-effector pose. A wide range of IK solvers exist, the majority of which operate on joint angles as parameters. Because the problem is highly nonlinear, these solvers are prone to local minima (among other troubles). I will introduce an alternate formulation of IK based on distance geometry, where a robot model is defined in terms of distances between rigidly-attached points. This alternative geometric description of the kinematics reveals an elegant equivalence between IK and the problem of low-rank Euclidean distance matrix completion. We use this connection to implement two novel solutions to IK for various articulated robots. The first is a Riemannian optimization-based approach which leverages the structure of the EDM manifold. The second solves a series of convex semidefinite relaxations of the distance-geometric problem. Both methods outperform many existing solvers on a variety of IK problems, some of which incorporate collision avoidance and joint limit constraints. Finally, I will describe a learned IK solver we have recently developed that is able to quickly generate sets of diverse approximate IK results for many different manipulators.

    Prof. Kelly will give his talk in person at RTH 115 and we will also host the talk over Zoom.

    Register in advance for this webinar at:


    After registering, attendees will receive a confirmation email containing information about joining the webinar.

    This lecture satisfies requirements for CSCI 591: Research Colloquium.

    Biography: Prof. Jonathan Kelly leads the Space & Terrestrial Autonomous Robotic Systems (STARS) Laboratory at the University of Toronto Institute for Aerospace Studies. His group carries out research primarily in the areas of robotic perception, planning, and manipulation. Prof. Kelly holds a Canada Research Chair (Tier II) in Collaborative Robotics and was Dean\'s Catalyst Professor (an early-career award for research excellence) from 2018 to 2021. Prior to joining the University of Toronto, he was a postdoctoral fellow in CSAIL at MIT, working with Prof. Nick Roy. He received his PhD degree in 2011 from the University of Southern California under the supervision of Prof. Gaurav Sukhatme. At USC, he was a member of the first cohort of Annenberg Fellows. Although he lives in Toronto, he still sneaks back to Los Angeles to go scuba diving whenever he can.

    Host: Stefanos Nikolaidis

    Webcast: https://usc.zoom.us/webinar/register/WN_ShCRcm1iTrq6ubaaY-8P5Q

    Location: Ronald Tutor Hall of Engineering (RTH) - 115

    WebCast Link: https://usc.zoom.us/webinar/register/WN_ShCRcm1iTrq6ubaaY-8P5Q

    Audiences: Everyone Is Invited

    Contact: Department of Computer Science


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