8 research outputs found
Interactive Co-Design of Form and Function for Legged Robots using the Adjoint Method
Our goal is to make robotics more accessible to casual users by reducing the
domain knowledge required in designing and building robots. Towards this goal,
we present an interactive computational design system that enables users to
design legged robots with desired morphologies and behaviors by specifying
higher level descriptions. The core of our method is a design optimization
technique that reasons about the structure, and motion of a robot in coupled
manner in order to achieve user-specified robot behavior, and performance. We
are inspired by the recent works that also aim to jointly optimize robot's form
and function. However, through efficient computation of necessary design
changes, our approach enables us to keep user-in-the-loop for interactive
applications. We evaluate our system in simulation by automatically improving
robot designs for multiple scenarios. Starting with initial user designs that
are physically infeasible or inadequate to perform the user-desired task, we
show optimized designs that achieve user-specifications, all while ensuring an
interactive design flow.Comment: 8 pages; added link of the accompanying vide
Curriculum Reinforcement Learning via Morphology-Environment Co-Evolution
Throughout long history, natural species have learned to survive by evolving
their physical structures adaptive to the environment changes. In contrast,
current reinforcement learning (RL) studies mainly focus on training an agent
with a fixed morphology (e.g., skeletal structure and joint attributes) in a
fixed environment, which can hardly generalize to changing environments or new
tasks. In this paper, we optimize an RL agent and its morphology through
``morphology-environment co-evolution (MECE)'', in which the morphology keeps
being updated to adapt to the changing environment, while the environment is
modified progressively to bring new challenges and stimulate the improvement of
the morphology. This leads to a curriculum to train generalizable RL, whose
morphology and policy are optimized for different environments. Instead of
hand-crafting the curriculum, we train two policies to automatically change the
morphology and the environment. To this end, (1) we develop two novel and
effective rewards for the two policies, which are solely based on the learning
dynamics of the RL agent; (2) we design a scheduler to automatically determine
when to change the environment and the morphology. In experiments on two
classes of tasks, the morphology and RL policies trained via MECE exhibit
significantly better generalization performance in unseen test environments
than SOTA morphology optimization methods. Our ablation studies on the two MECE
policies further show that the co-evolution between the morphology and
environment is the key to the success
Computational design of skinned Quad-Robots
We present a computational design system that assists users to model, optimize, and fabricate quad-robots with soft skins. Our system addresses the challenging task of predicting their physical behavior by fully integrating the multibody dynamics of the mechanical skeleton and the elastic behavior of the soft skin. The developed motion control strategy uses an alternating optimization scheme to avoid expensive full space time-optimization, interleaving space-time optimization for the skeleton, and frame-by-frame optimization for the full dynamics. The output are motor torques to drive the robot to achieve a user prescribed motion trajectory. We also provide a collection of convenient engineering tools and empirical manufacturing guidance to support the fabrication of the designed quad-robot. We validate the feasibility of designs generated with our system through physics simulations and with a physically-fabricated prototype