Geometric and Algebraic Modeling
Date & Time: Tuesday, September 29, 2026 | 17:00 - 18:40
Place: Campus South, Mathematics Building 20.30 [Englerstraße 02], Room 2.059
Chairs: Edwin León-Cardenal
Abstract:
Confirmed Speakers
Speaker: Àlex Garcia-Herranz (Universitat Politècnica de Catalunya)
Title: Lie-Poisson Reduction and Stability of Kirchhoff Rods Under Gravity.
Abstract: Modeling heavy continuous elastic rods under gravity typically requires computationally intensive discretizations or simplifying approximations. This work addresses these limitations by developing a continuous mathematical model and a low-dimensional representation of Kirchhoff rods suitable for robotic control. While gravity breaks the classical left-invariance symmetry of the Hamiltonian on , we recover a reducible geometric structure by embedding the system into the semidirect product group . Lie-Poisson reduction then projects the system from the cotangent bundle to a low-dimensional dual Lie algebra.
We validate this framework by recovering the classical balance laws for internal forces and moments. Crucially for robotic applications, we prove that the mapping from the initial base wrench to the corresponding equilibrium rod configuration is a global diffeomorphism, establishing the six-dimensional base wrench space as a global control atlas.. Combined with a proof of path-connectedness for segmented stable configurations, this geometric formulation provides a foundation for global motion planning and safe manipulation of soft continuum robots and cables.
Speaker: Werner Seiler (Universität Kassel)
Title: Geometric Modelling of Singular Initial and Boundary Value Problems: Theory and Numerics
Abstract: We consider quasilinear ordinary differential equations both theoretically and numerically. We call an initial or boundary value problem singular, if at an initial or boundary condition the coefficient of a derivative of highest order vanishes. In such a situation, the well-known existence and uniqueness theorems cannot be applied and also classical numerical integrators typically break down in the vicinity of such a singularity. Using a geometric view of a differential equation as a submanifold in a suitable jet bundle, we define an explicit dynamical system on this submanifold and relate questions of existence, (non)uniqueness and regularity of solutions to standard problems in dynamical systems theory. Furthermore, this point of view leads in a straightforward manner to a simple and robust numerical approach to singular initial and boundary value problems. As examples, we will consider classical equations like Lane-Emden or Thomas-Fermi and show how the for applications relevant initial and boundary value problems can be solved in a few lines of Maple code.
Speaker: Abhilash Nayak (Universitat Politècnica de Catalunya)
Title: Geometric Modeling of Kinematic Grasp Constraints for Robotic Cloth Folding
Abstract: Robotic cloth folding requires coupling the rigid motion of a gripper with the deformation of a flexible surface. We present a lightweight geometric interface in which the gripper is modeled by a pose, a jaw state, and an attached grasping volume, represented as a box or a square pyramid in the gripper frame. When the gripper closes, cloth vertices inside this volume are selected, stored in local coordinates, and transported by quaternion-based rigid transformations. The resulting constraints are integrated into an inextensible cloth simulator and tested on a Franka robot arm by performing a corner-folding motion, highlighting the role of grasp support and gripper orientation.