Search

Tactile sensing is critical to fine-grained, contact-rich manipulation tasks, such as insertion and assembly. Prior research has shown the possibility of learning tactile-guided policy from teleoperated demonstration data. However, to provide the demonstration, human users often rely on visual feedback to control the robot. This creates a gap between the sensing modality used for controlling the robot (visual) and the modality of interest (tactile). To bridge this gap, we introduce "MimicTouch", a novel framework for learning policies directly from demonstrations provided by human users with their hands. The key innovations are i) a human tactile data collection system which collects multi-modal tactile dataset for learning human's tactile-guided control strategy, ii) an imitation learning-based framework for learning human's tactile-guided control strategy through such data, and iii) an online residual RL framework to bridge the embodiment gap between the human hand and the robot gripper. Through comprehensive experiments, we highlight the efficacy of utilizing human's tactile-guided control strategy to resolve contact-rich manipulation tasks. The project website is at https://sites.google.com/view/MimicTouch., Comment: Accepted by CoRL 2024, Best Paper Award at NeurIPS 2023 Touch Processing Workshop

Passive solar desalination is an emerging low-cost technology for fresh water production. State of the art desalinators typically evaporate water using wicking structures to achieve high solar-to-vapor efficiency by minimizing heat loss. However, wicking structures cannot reject salt continuously which limits the operating duration of the desalinators to several hours before the devices are turned off to reject salt. While significant research has focused on developing efficient evaporators to achieve high solar-to-vapor efficiency, inefficient condensers have become the bottleneck for the overall solar-to-water efficiency. To overcome these challenges, we designed a passive inverted single stage solar membrane desalinator that achieves continuous desalination and salt rejection. By flowing salt water on a radiative absorbing, porous, hydrophobic evaporator membrane using gravity, salt continuously diffuses away from the membrane while allowing heated water vapor to transport to and condense on a cooler microporous membrane below. Our design utilizes thin-film condensation on a microporous membrane which offers ample three-phase contact region to enhance condensation phase change heat transfer. By condensing within the microporous membrane, we reduce the gap distance between the condenser and evaporator membranes, which reduces the vapor transport resistance. We experimentally demonstrated a record-high continuous desalination and salt rejection test duration of 7 days under one-sun. Despite an increased convection heat loss necessary for salt rejection on the evaporator, our desalinator still achieved a water-collection rate of 0.487 $kg$ $m^{-2}h^{-1}$, which corresponds to a 32.2% solar-to-water efficiency. This work signifies an improvement in the robustness of current state of the art desalinators and presents a new architecture to further optimize passive solar desalinators., Comment: 24 pages, 9 figures