Task Space Angular Velocity Blending for Real-Time Trajectory Generation

The invention is embodied in a method of controlling a robot manipulator moving toward a target frame F(sub 0) with a target velocity v(sub 0) including a linear target velocity v and an angular target velocity omega(sub 0) to smoothly and continuously divert the robot manipulator to a subsequent frame F(sub 1) by determining a global transition velocity v(sub 1), the global transition velocity including a linear transition velocity v(sub 1) and an angular transition velocity omega(sub 1), defining a blend time interval 2(tau)(sub 0) within which the global velocity of the robot manipulator is to be changed from a global target velocity v(sub 0) to the global transition velocity v(sub 1) and dividing the blend time interval 2(tau)(sub 0) into discrete time segments (delta)t. During each one of the discrete time segments delta t of the blend interval 2(tau)(sub 0), a blended global velocity v of the manipulator is computed as a blend of the global target velocity v(sub 0) and the global transition velocity v(sub 1), the blended global velocity v including a blended angular velocity omega and a blended linear velocity v, and then, the manipulator is rotated by an incremental rotation corresponding to an integration of the blended angular velocity omega over one discrete time segment (delta)t

Progress in Development of the Axel Rovers

Progress has been made in the development of a family of robotic land vehicles having modular and minimalist design features chosen to impart a combination of robustness, reliability, and versatility. These vehicles at earlier stages of development were described in two previous NASA Tech Briefs articles: "Reconfigurable Exploratory Robotic Vehicles" (NPO-20944), Vol. 25, No. 7 (July 2001), page 56; and "More About Reconfigurable Exploratory Robotic Vehicles" (NPO-30890), Vol. 33, No. 8 (August 2009), page 40. Conceived for use in exploration of the surfaces of Mars and other remote planets, these vehicles could also be adapted to terrestrial applications, including exploration of volcanic craters or other hostile terrain, military reconnaissance, inspection of hazardous sites, and searching for victims of earthquakes, landslides, avalanches, or mining accidents. In addition, simplified versions of these vehicles might be marketable as toys. The most basic module in this family of reconfigurable robots is the Axel rover, which has a cylindrical body with two main wheels and a trailing link. Inside its body are three motors and associated mechanisms for driving the two wheels and for rotating the link 360 around its symmetrical body. The actuated link serves several purposes: It is used as a lever arm to react to the wheels thrust to move Axel in multiple directions. It is used to rotate the Axel housing in order to tilt, to the desired angle, any sensors and instruments mounted on or in the Axel housing. It provides an alternative mobility mode, which is primarily used in its tethered configuration. Turn ing the link into the ground in lieu of driving the wheels causes the Axel housing and wheels to roll as a unit and thereby leads to a tumbling motion along the ground. With a tether mounted around Axel s cylindrical body, the link serves as a winch mechanism to reel and unreel the tether raising and lowering Axel over steep and vertical surfaces (Figure 1). Sensors, computation, and communication modules are also housed inside Axel s body. A pair of stereo vision cameras provides three-dimensional view for autonomous navigation and avoiding obstacles. Inertial sensors determine the tilt of the robot and are used for estimating its motion. In a fully developed version, power would be supplied by rechargeable batteries aboard Axel; at the time of reporting the information for this article, power was supplied from an external source via a cable. In and of itself, the Axel rover is fully capable of traversing and sampling terrains on planetary surfaces. By use of only the two main wheel actuators and the caster link actuator, Axel can be made to follow an arbitrary path, turn in place, and operate upside- down or right-side-up. If operated in a tethered configuration, as shown in Figure 1, it can be made to move down and up a steep crater wall, descend from an overhang to a cave, and ascend from the cave back to the overhang, all by use of the same three actuators. Such tethered operation could be useful in searching for accident victims or missing persons in mines, caves, and rubble piles. Running the tether through the caster link enhances the stability of Axel and provides a restoring force that keeps the link off the ground for the most part during operation on a steep slope. In its extended configuration, two Axel modules can dock to either side of a payload module to form the four wheeled Axel2 rover (Figure 2). Additional payload and Axel modules can dock to either side of the Axel2 to form the Axel3 rover, extending its payload capacity and its mobility capabilities

Petition for a Writ of Certiorari to the United States Court of Appeals for the Sixth Circuit, \u3cem\u3eTVA v. Hill\u3c/em\u3e, No. 76-1701

Petition requesting that the United States Supreme Court hear an appeal to the decision of the United States Court of Appeals for the Sixth Circuit in Tennessee Valley Authority v. Hiram G. Hill Jr., et al.

Brief for the Petitioner, \u3cem\u3eTVA v. Hill\u3c/em\u3e, No. 76-1701

Brief for the petitioner in the case of Tennessee Valley Authority v. Hiram G. Hill Jr., et al., heard by the United States Supreme Court in the October Term of 1977

Toll-like receptor 8 functions as a negative regulator of neurite outgrowth and inducer of neuronal apoptosis

Toll receptors in Drosophila melanogaster function in morphogenesis and host defense. Mammalian orthologues of Toll, the Toll-like receptors (TLRs), have been studied extensively for their essential functions in controlling innate and adaptive immune responses. We report that TLR8 is dynamically expressed during mouse brain development and localizes to neurons and axons. Agonist stimulation of TLR8 in cultured cortical neurons causes inhibition of neurite outgrowth and induces apoptosis in a dissociable manner. Our evidence indicates that such TLR8-mediated neuronal responses do not involve the canonical TLR–NF-κB signaling pathway. These findings reveal novel functions for TLR8 in the mammalian nervous system that are distinct from the classical role of TLRs in immunity

Locomotive Crash Energy Management Vehicle-to-Vehicle Tests 1 & 2: Analyses and Test Results

6913G618F500083Crash energy management (CEM) components which can be integrated into the end structure of a locomotive were developed: a push-back coupler and a deformable anti-climber. These components are designed to inhibit override and improve crashworthiness for equipped locomotives in a wide range of collisions. A full-scale dynamic impact test program has been designed to evaluate the CEM system. Two sets of coupling tests validated finite element models. Two CEM locomotive vehicle-to-vehicle collision tests and a train-to-train collision test are planned. This report describes the analyses and test results of both the first and second vehicle-to-vehicle impact tests

Taking Snapshots, Living the Picture: The Kodak Company's Making of Photographic Biography

In this article I explore how George Eastman and the Eastman Kodak Company encouraged early twentieth-century camera users to think of snapshots as pictorial biographies. Analysing a wide selection of articles from the Kodakery, one of Kodak’s most popular magazines in the first half of the twentieth century, I demonstrate that the company endeavoured to secure its prominence in the photographic market by encouraging members of the public to integrate picture-taking into everyday life, and regard photographs as self-contained repositories of biographical details. To this end, Kodak framed the speedy pace of life that characterised the practice of being in the industrial world as a reality that allegedly weakened the human eye and mind’s ability to process the experience of life itself. Introducing the idea of the camera and picturetaking as the ultimate cures for this purported human deficiency, Kodak provided camera users with advice that helped to cement an understanding of photographs as surrogates of both the changing human body and individual subjects’ experiences in time and space. As in popular culture, and sometimes also in academia, photographs are still widely regarded as pictorial biographies, I argue that considering the popular photographic industry’s role in shaping photographic practices and photographs’ perceived meanings can help clarify the relationship between photography and life-writing

Associations between circulating interferon and kynurenine/tryptophan pathway metabolites: support for a novel potential mechanism for cognitive dysfunction in SLE

OBJECTIVE: Quinolinic acid (QA), a kynurenine (KYN)/tryptophan (TRP) pathway metabolite, is an N-methyl-D-aspartate receptor agonist that can produce excitotoxic neuron damage. Type I and II interferons (IFNs) stimulate the KYN/TRP pathway, producing elevated QA/kynurenic acid (KA), a potential neurotoxic imbalance that may contribute to SLE-mediated cognitive dysfunction. We determined whether peripheral blood interferon-stimulated gene (ISG) expression associates with elevated serum KYN:TRP and QA:KA ratios in SLE. METHODS: ISG expression (whole-blood RNA sequencing) and serum metabolite ratios (high-performance liquid chromatography) were measured in 72 subjects with SLE and 73 healthy controls (HCs). ISG were identified from published gene sets and individual IFN scores were derived to analyse associations with metabolite ratios, clinical parameters and neuropsychological assessments. SLE analyses were grouped by level of ISG expression ('IFN high', 'IFN low' and 'IFN similar to HC') and level of monocyte-associated gene expression (using CIBERSORTx). RESULTS: Serum KYN:TRP and QA:KA ratios were higher in SLE than in HC (p<0.01). 933 genes were differentially expressed ≥2-fold in SLE versus HC (p<0.05). 70 of the top 100 most highly variant genes were ISG. Approximately half of overexpressed genes that correlated with KYN:TRP and QA:KA ratios (p<0.05) were ISG. In 36 IFN-high subjects with SLE, IFN scores correlated with KYN:TRP ratios (p<0.01), but not with QA:KA ratios. Of these 36 subjects, 23 had high monocyte-associated gene expression, and in this subgroup, the IFN scores correlated with both KY:NTRP and QA:KA ratios (p<0.05). CONCLUSIONS: High ISG expression correlated with elevated KYN:TRP ratios in subjects with SLE, suggesting IFN-mediated KYN/TRP pathway activation, and with QA:KA ratios in a subset with high monocyte-associated gene expression, suggesting that KYN/TRP pathway activation may be particularly important in monocytes. These results need validation, which may aid in determining which patient subset may benefit from therapeutics directed at the IFN or KYN/TRP pathways to ameliorate a potentially neurotoxic QA/KA imbalance