Abstract: Presented herein are embodiments of a two-stage methodology that integrates data-driven imitation learning and model-based trajectory optimization to generate optimal trajectories for autonomous excavators. In one or more embodiments, a deep neural network using demonstration data to mimic the operation patterns of human experts under various terrain states, including their geometry shape and material type. A stochastic trajectory optimization methodology is used to improve the trajectory generated by the neural network to ensure kinematics feasibility, improve smoothness, satisfy hard constraints, and achieve desired excavation volumes. Embodiments were tested on a Franka robot arm equipped with a bucket end-effector. Embodiments were also evaluated on different material types, such as sand and rigid blocks. Experimental results showed that embodiments of the two-stage methodology that comprises combining expert knowledge and model optimization increased the excavation weights by up to 24.

Abstract: A method of manufacturing a lead assembly of a cryogenic system is provided. The method includes developing a three-dimensional (3D) model of a heat exchanger. The heat exchanger includes a plurality of channels extending longitudinally through the heat exchanger from the first end to the second end, the plurality of channels forming a plurality of thermal surfaces within the heat exchanger, the heat exchanger having a transverse cross section. The method further includes modifying the 3D model by at least one of reducing an area of the cross section and increasing the plurality of thermal surfaces. The method also includes additively manufacturing the heat exchanger using an electrically-conductive and thermally-conductive material according to the modified 3D model. Further, the method includes providing a high temperature superconductor (HTS) assembly that includes an HTS strip, and connecting the HTS assembly to the heat exchanger at the second end of the heat exchanger.

Abstract: A method of manufacturing a lead assembly of a cryogenic system is provided. The method includes developing a three-dimensional (3D) model of a heat exchanger. The heat exchanger includes a plurality of channels extending longitudinally through the heat exchanger from the first end to the second end, the plurality of channels forming a plurality of thermal surfaces within the heat exchanger, the heat exchanger having a transverse cross section. The method further includes modifying the 3D model by at least one of reducing an area of the cross section and increasing the plurality of thermal surfaces. The method also includes additively manufacturing the heat exchanger using an electrically-conductive and thermally-conductive material according to the modified 3D model. Further, the method includes providing a high temperature superconductor (HTS) assembly that includes an HTS strip, and connecting the HTS assembly to the heat exchanger at the second end of the heat exchanger.