Hierarchical Planning for Rope Manipulation using Knot Theory and a Learned Inverse Model
CORL 2023
This work considers planning the manipulation of deformable 1-dimensional objects, such
as ropes or cables, specifically to tie knots. We propose TWISTED: Tying With Inverse
model and Search in Topological space Excluding Demos, a hierarchical planning approach
which, at the high level, uses ideas from knot-theory to plan a sequence of rope
configurations, while at the low level uses a neural-network inverse model to move
between the configurations in the high-level plan. To train the neural network, we
propose a self-supervised approach, where we learn from random movements of the rope.
To focus the random movements on interesting configurations, such as knots, we propose
a non-uniform sampling method tailored for this domain. In a simulation, we show that
our approach can plan significantly faster and more accurately than baselines. We also
show that our plans are robust to parameter changes in the physical simulation,
suggesting future applications via sim2real.