132 research outputs found
Learning to Navigate Cloth using Haptics
We present a controller that allows an arm-like manipulator to navigate
deformable cloth garments in simulation through the use of haptic information.
The main challenge of such a controller is to avoid getting tangled in, tearing
or punching through the deforming cloth. Our controller aggregates force
information from a number of haptic-sensing spheres all along the manipulator
for guidance. Based on haptic forces, each individual sphere updates its target
location, and the conflicts that arise between this set of desired positions is
resolved by solving an inverse kinematic problem with constraints.
Reinforcement learning is used to train the controller for a single
haptic-sensing sphere, where a training run is terminated (and thus penalized)
when large forces are detected due to contact between the sphere and a
simplified model of the cloth. In simulation, we demonstrate successful
navigation of a robotic arm through a variety of garments, including an
isolated sleeve, a jacket, a shirt, and shorts. Our controller out-performs two
baseline controllers: one without haptics and another that was trained based on
large forces between the sphere and cloth, but without early termination.Comment: Supplementary video available at https://youtu.be/iHqwZPKVd4A.
Related publications http://www.cc.gatech.edu/~karenliu/Robotic_dressing.htm
Human-like Energy Management Based on Deep Reinforcement Learning and Historical Driving Experiences
Development of hybrid electric vehicles depends on an advanced and efficient
energy management strategy (EMS). With online and real-time requirements in
mind, this article presents a human-like energy management framework for hybrid
electric vehicles according to deep reinforcement learning methods and
collected historical driving data. The hybrid powertrain studied has a
series-parallel topology, and its control-oriented modeling is founded first.
Then, the distinctive deep reinforcement learning (DRL) algorithm, named deep
deterministic policy gradient (DDPG), is introduced. To enhance the derived
power split controls in the DRL framework, the global optimal control
trajectories obtained from dynamic programming (DP) are regarded as expert
knowledge to train the DDPG model. This operation guarantees the optimality of
the proposed control architecture. Moreover, the collected historical driving
data based on experienced drivers are employed to replace the DP-based
controls, and thus construct the human-like EMSs. Finally, different categories
of experiments are executed to estimate the optimality and adaptability of the
proposed human-like EMS. Improvements in fuel economy and convergence rate
indicate the effectiveness of the constructed control structure.Comment: 8 pages, 10 figure
SayTap: Language to Quadrupedal Locomotion
Large language models (LLMs) have demonstrated the potential to perform
high-level planning. Yet, it remains a challenge for LLMs to comprehend
low-level commands, such as joint angle targets or motor torques. This paper
proposes an approach to use foot contact patterns as an interface that bridges
human commands in natural language and a locomotion controller that outputs
these low-level commands. This results in an interactive system for quadrupedal
robots that allows the users to craft diverse locomotion behaviors flexibly. We
contribute an LLM prompt design, a reward function, and a method to expose the
controller to the feasible distribution of contact patterns. The results are a
controller capable of achieving diverse locomotion patterns that can be
transferred to real robot hardware. Compared with other design choices, the
proposed approach enjoys more than 50% success rate in predicting the correct
contact patterns and can solve 10 more tasks out of a total of 30 tasks. Our
project site is: https://saytap.github.io
Continuous Versatile Jumping Using Learned Action Residuals
Jumping is essential for legged robots to traverse through difficult
terrains. In this work, we propose a hierarchical framework that combines
optimal control and reinforcement learning to learn continuous jumping motions
for quadrupedal robots. The core of our framework is a stance controller, which
combines a manually designed acceleration controller with a learned residual
policy. As the acceleration controller warm starts policy for efficient
training, the trained policy overcomes the limitation of the acceleration
controller and improves the jumping stability. In addition, a low-level
whole-body controller converts the body pose command from the stance controller
to motor commands. After training in simulation, our framework can be deployed
directly to the real robot, and perform versatile, continuous jumping motions,
including omni-directional jumps at up to 50cm high, 60cm forward, and
jump-turning at up to 90 degrees. Please visit our website for more results:
https://sites.google.com/view/learning-to-jump.Comment: To be presented at L4DC 202
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