挑戦的地形探査のための自律脚型クライミングロボット

要約のみTohoku University吉田和哉課

Integration of Vision-based Object Detection and Grasping for Articulated Manipulator in Lunar Conditions

The integration of vision-based frameworks to achieve lunar robot applications faces numerous challenges such as terrain configuration or extreme lighting conditions. This paper presents a generic task pipeline using object detection, instance segmentation and grasp detection, that can be used for various applications by using the results of these vision-based systems in a different way. We achieve a rock stacking task on a non-flat surface in difficult lighting conditions with a very good success rate of 92%. Eventually, we present an experiment to assemble 3D printed robot components to initiate more complex tasks in the future

Lower Gravity Demonstratable Testbed for Space Robot Experiments

In developing mobile robots for exploration on the planetary surface, it is crucial to evaluate the robot's performance, demonstrating the harsh environment in which the robot will actually be deployed. Repeatable experiments in a controlled testing environment that can reproduce various terrain and gravitational conditions are essential. This paper presents the development of a minimal and space-saving indoor testbed, which can simulate steep slopes, uneven terrain, and lower gravity, employing a three-dimensional target tracking mechanism (active xy and passive z) with a counterweight.Comment: 2 pages, 3 figures, paper accepted for the SII 2024 (IEEE/SICE International Symposium on System Integration) (Updated references formatting

Identification of the basic amino acid residues on the PsbP protein involved in the electrostatic interaction with photosystem II

AbstractThe PsbP protein is an extrinsic subunit of photosystem II (PSII) that is essential for photoautotrophic growth in higher plants. Several crystal structures of PsbP have been reported, but the binding topology of PsbP in PSII has not yet been clarified. In this study, we report that the basic pocket of PsbP, which consists of conserved Arg48, Lys143, and Lys160, is important for the electrostatic interaction with the PSII complex. Our release-reconstitution experiment showed that the binding affinities of PsbP-R48A, -K143A, and -K160A mutated proteins to PSII were lower than that of PsbP-WT, and triple mutations of these residues greatly diminished the binding affinity to PSII. Even when maximum possible binding had occurred, the R48A, K143A, and K160A proteins showed a reduced ability to restore the rate of oxygen evolution at low chloride concentrations. Fourier transform infrared resonance (FTIR) difference spectroscopy results were consistent with the above finding, and suggested that these mutated proteins were not able to induce the normal conformational change around the Mn cluster during S1 to S2 transition. Finally, chemical cross-linking experiments suggested that the interaction between the N-terminus of PsbP with PsbE was inhibited by these mutations. These data suggest that the basic pocket of PsbP is important for proper association and interaction with PSII. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: Keys to Produce Clean Energy

OmniLRS: A Photorealistic Simulator for Lunar Robotics

Developing algorithms for extra-terrestrial robotic exploration has always been challenging. Along with the complexity associated with these environments, one of the main issues remains the evaluation of said algorithms. With the regained interest in lunar exploration, there is also a demand for quality simulators that will enable the development of lunar robots. % In this paper, we explain how we built a Lunar simulator based on Isaac Sim, Nvidia's robotic simulator. In this paper, we propose Omniverse Lunar Robotic-Sim (OmniLRS) that is a photorealistic Lunar simulator based on Nvidia's robotic simulator. This simulation provides fast procedural environment generation, multi-robot capabilities, along with synthetic data pipeline for machine-learning applications. It comes with ROS1 and ROS2 bindings to control not only the robots, but also the environments. This work also performs sim-to-real rock instance segmentation to show the effectiveness of our simulator for image-based perception. Trained on our synthetic data, a yolov8 model achieves performance close to a model trained on real-world data, with 5% performance gap. When finetuned with real data, the model achieves 14% higher average precision than the model trained on real-world data, demonstrating our simulator's photorealism.% to realize sim-to-real. The code is fully open-source, accessible here: https://github.com/AntoineRichard/LunarSim, and comes with demonstrations.Comment: 7 pages, 4 figure

Enabling Faster Locomotion of Planetary Rovers with a Mechanically-Hybrid Suspension

The exploration of the lunar poles and the collection of samples from the martian surface are characterized by shorter time windows demanding increased autonomy and speeds. Autonomous mobile robots must intrinsically cope with a wider range of disturbances. Faster off-road navigation has been explored for terrestrial applications but the combined effects of increased speeds and reduced gravity fields are yet to be fully studied. In this paper, we design and demonstrate a novel fully passive suspension design for wheeled planetary robots, which couples a high-range passive rocker with elastic in-wheel coil-over shock absorbers. The design was initially conceived and verified in a reduced-gravity (1.625 m/s$^2$) simulated environment, where three different passive suspension configurations were evaluated against a set of challenges--climbing steep slopes and surmounting unexpected obstacles like rocks and outcrops--and later prototyped and validated in a series of field tests. The proposed mechanically-hybrid suspension proves to mitigate more effectively the negative effects (high-frequency/high-amplitude vibrations and impact loads) of faster locomotion (>1 m/s) over unstructured terrains under varied gravity fields. This lowers the demand on navigation and control systems, impacting the efficiency of exploration missions in the years to come.Comment: 8 pages, 13 figure

Development of flexible nanocarriers for siRNA delivery into tumor tissue

Various non-viral delivery systems for small interfering RNAs (siRNA) have been developed. Such delivery systems generally exhibit tightly formed spherical structures. While such carriers have demonstrated good transfection activity in mono-layered cell systems, effects against solid tumors are often less apparent and difficult to demonstrate, likely due to the rigid structures of the carriers, which may prevent penetration to deeper regions within tumor tissue. Herein, we developed a flexible nanocarrier (FNC) system that is able to penetrate to deeper regions within tumor tissue. Specifically, we employed previously found flexible polyplexes comprised of siRNA and poly-L-lysine as wick structures for the preparation of FNCs. FNCs were constructed by coating the wick structures with lipids using a liposomal membrane fusion method. The diameters of the resulting FNCs were ca. 170 nm, and the shapes were non-spherical. Lipid coating was confirmed using a nuclease resistance assay. Furthermore, FNCs showed significant RNA interference effects, comparable to Lipofectamine 2000, in a mono-layered cell system. To accelerate tumor penetration, the FNC surface was modified with polyethylene glycol (PEG) and the tight junction opener peptide AT1002. Surface-modified FNCs demonstrated effective penetrability into a cancer spheroid. Thus, we developed a novel and unique tumor-penetrable siRNA FNC system

Mobility Strategy of Multi-Limbed Climbing Robots for Asteroid Exploration

Mobility on asteroids by multi-limbed climbing robots is expected to achieve our exploration goals in such challenging environments. We propose a mobility strategy to improve the locomotion safety of climbing robots in such harsh environments that picture extremely low gravity and highly uneven terrain. Our method plans the gait by decoupling the base and limbs' movements and adjusting the main body pose to avoid ground collisions. The proposed approach includes a motion planning that reduces the reactions generated by the robot's movement by optimizing the swinging trajectory and distributing the momentum. Lower motion reactions decrease the pulling forces on the grippers, avoiding the slippage and flotation of the robot. Dynamic simulations and experiments demonstrate that the proposed method could improve the robot's mobility on the surface of asteroids.Comment: Submitted version of paper accepted for presentation at the CLAWAR 2023 (26th International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines

Experimental Verification of Robotic Landing and Locomotion on Asteroids

peer reviewedIn-situ explorations of asteroids and other small celestial bodies are crucial to collect surface samples, which could be the key to understanding the formation of our solar system. Studying the composition of asteroids is also important for future planetary defense and mining resources for in-situ utilization. However, the weak gravitational field poses many challenges for robotic landing and locomotion scenarios on the surface of asteroids. Legged climbing robots are expected to perform well under microgravity, as they can maintain surface attachment, preventing undesired flotation and uncontrolled bouncing. Therefore, we need to consider methods to plan and control the landing and locomotion of climbing robots on asteroids. In this study, we have performed experiments regarding the emulation of two scenarios; 1- Landing, 2- Locomotion. For both landing and locomotion scenarios, separate PD controllers have been utilized

Non-Periodic Gait Planning Based on Salient Region Detection for a Planetary Cave Exploration Robot

A limbed climbing robot can traverse uneven and steep terrain, such as Lunar/Martian caves. Towards the autonomous operation of the robot, we first present a method to detect topographically salient regions in 3D point cloud as the robot ’s graspable targets, and next, we introduce a strategy to plan a non-periodic gait for the robot from the detected discrete graspable options. The proposed gait planner is implemented and validated in our open dynamic climbing robot simulation platform assuming the 3 kg class four-limbed climbing robot testbed moving over steep and uneven Lunar terrain.International Symposium on Artificial Intelligence, Robotics and Automation in Space (i-SAIRAS 2020), October 19-23, 2020, Los Angles, CA, USA（新型コロナ感染拡大に伴い、オンライン開催に変更