Actuators for a space manipulator

The robotic manipulator can be decomposed into distinct subsytems. One particular area of interest of mechanical subsystems is electromechanical actuators (or drives). A drive is defined as a motor with an appropriate transmission. An overview is given of existing, as well as state-of-the-art drive systems. The scope is limited to space applications. A design philosophy and adequate requirements are the initial steps in designing a space-qualified actuator. The focus is on the d-c motor in conjunction with several types of transmissions (harmonic, tendon, traction, and gear systems). The various transmissions will be evaluated and key performance parameters will be addressed in detail. Included in the assessment is a shuttle RMS joint and a MSFC drive of the Prototype Manipulator Arm. Compound joints are also investigated. Space imposes a set of requirements for designing a high-performance drive assembly. Its inaccessibility and cryogenic conditions warrant special considerations. Some guidelines concerning these conditions are present. The goal is to gain a better understanding in designing a space actuator

RTJ-303: Variable geometry, oblique wing supersonic aircraft

This document is a preliminary design of a High Speed Civil Transport (HSCT) named the RTJ-303. It is a 300 passenger, Mach 1.6 transport with a range of 5000 nautical miles. It features four mixed-flow turbofan engines, variable geometry oblique wing, with conventional tail-aft control surfaces. The preliminary cost analysis for a production of 300 aircraft shows that flyaway cost would be 183 million dollars (1992) per aircraft. The aircraft uses standard jet fuel and requires no special materials to handle aerodynamic heating in flight because the stagnation temperatures are approximately 130 degrees Fahrenheit in the supersonic cruise condition. It should be stressed that this aircraft could be built with today's technology and does not rely on vague and uncertain assumptions of technology advances. Included in this report are sections discussing the details of the preliminary design sequence including the mission to be performed, operational and performance constraints, the aircraft configuration and the tradeoffs of the final choice, wing design, a detailed fuselage design, empennage design, sizing of tail geometry, and selection of control surfaces, a discussion on propulsion system/inlet choice and their position on the aircraft, landing gear design including a look at tire selection, tip-over criterion, pavement loading, and retraction kinematics, structures design including load determination, and materials selection, aircraft performance, a look at stability and handling qualities, systems layout including location of key components, operations requirements maintenance characteristics, a preliminary cost analysis, and conclusions made regarding the design, and recommendations for further study

Flow Control Applications

Flow control has a long history with many successes across a plethora of applications. This report addresses the characteristics of the approaches that are actually used, why they are used, the many approaches that are not used, and why. Analysis indicates ways forward to increase applicability/usefulness, and efficiency of flow control research. Overall, greater and more effective progress in flow control requires utilization of far more detailed information early in the research process regarding application details and requirements

Preliminary Electrical Designs for CTEx and AFIT Satellite Ground Station

This thesis outlines the design of the electrical components for the space-based ChromoTomography Experiment (CTEx). CTEx is the next step in the development of high-speed chromotomography at the Air Force Institute of Technology. The electrical design of the system is challenging due to the large amount of data that is acquired by the imager and the limited resources that is inherent with space-based systems. Additional complication to the design is the need to know the angle of a spinning prism that is in the field of view very precisely for each image. Without this precise measurement any scene that is reconstructed from the data will be blurry and incomprehensible. This thesis also outlines how the control software for the CTEx space system should be created. The software ow is a balance of complex real time target pointing angles and simplicity to allow the system to function as quick as possible. This thesis also discusses the preliminary design for an AFIT satellite ground station based upon the design of the United States Air Force Academy\u27s ground station. The AFIT ground station will be capable of commanding and controlling satellites produced by USAFA and satellites produced by a burgeoning small satellite program at AFIT

The 29th Aerospace Mechanisms Symposium

The proceedings of the 29th Aerospace Mechanisms Symposium, which was hosted by NASA Johnson Space Center and held at the South Shore Harbour Conference Facility on May 17-19, 1995, are reported. Technological areas covered include actuators, aerospace mechanism applications for ground support equipment, lubricants, pointing mechanisms joints, bearings, release devices, booms, robotic mechanisms, and other mechanisms for spacecraft

Index to NASA Tech Briefs, 1975

This index contains abstracts and four indexes--subject, personal author, originating Center, and Tech Brief number--for 1975 Tech Briefs

Electronic/electric technology benefits study

The benefits and payoffs of advanced electronic/electric technologies were investigated for three types of aircraft. The technologies, evaluated in each of the three airplanes, included advanced flight controls, advanced secondary power, advanced avionic complements, new cockpit displays, and advanced air traffic control techniques. For the advanced flight controls, the near term considered relaxed static stability (RSS) with mechanical backup. The far term considered an advanced fly by wire system for a longitudinally unstable airplane. In the case of the secondary power systems, trades were made in two steps: in the near term, engine bleed was eliminated; in the far term bleed air, air plus hydraulics were eliminated. Using three commercial aircraft, in the 150, 350, and 700 passenger range, the technology value and pay-offs were quantified, with emphasis on the fiscal benefits. Weight reductions deriving from fuel saving and other system improvements were identified and the weight savings were cycled for their impact on TOGW (takeoff gross weight) and upon the performance of the airframes/engines. Maintenance, reliability, and logistic support were the other criteria

Desenvolvimento de um veículo inovador para armazéns automáticos

Intralogistics is increasingly a matter of research and development as a form of optimization, automation, integration and management of the flow of materials and information that circulate within a business unit. With a strong connection to material handling equipment and automation solutions, intralogistics has proved to be one of the main factors responsible for something that is already happening: a fourth industrial revolution where it is possible to convert warehouses and manufacturing units into intelligent environments where the entire process can be controlled and supervised through a single system. It became necessary to develop more and more innovative and efficient solutions to the constant diversity of challenges proposed by the market. In this sense, it was proposed to develop something innovative within the area of Automated Storage and Retrieval Systems (AS/RS), a technology increasingly sought after by today's manufacturing plants. As such, the goal was to improve the most emergent AS/RS in recent years: the Pallet/Box Shuttle AS/RS. In order to achieve the proposed objective, it was necessary to analyze all the existing solutions in the market and, principally, to find the main points to be improved and the direction to follow in order to innovate an already advanced solution. The results show a robotized solution where it was possible to increase the automation of the operations in the storage systems and improve the responsiveness of the system, taking this solution to a new level.A intralogística é cada vez mais uma área de investigação e desenvolvimento como uma forma de otimização, automação, integração e gestão do fluxo de materiais e informações que circulam dentro de uma unidade de negócios. Com uma forte ligação com equipamentos de manipulação de materiais e soluções de automação, a intralogística provou ser um dos principais fatores responsáveis por algo que já está a acontecer: uma quarta revolução industrial, onde é possível converter armazéns e unidades fabris em ambientes inteligentes, onde todo o processo pode ser controlado e supervisionado através de um único sistema. Tornou-se necessário desenvolver soluções cada vez mais inovadoras e eficientes para a constante diversidade de desafios propostos pelo mercado. Nesse sentido, propôs-se desenvolver algo inovador dentro da área dos Armazéns Automáticos, uma solução cada vez mais procurada pelas unidades fabris de hoje. Como tal, estabeleceu-se o objetivo de melhorar o tipo de Armazém Automático mais emergente dos últimos anos: o Armazém Automático com Veículos Satélite para Caixas ou Paletes. Para alcançar o objetivo proposto, foi necessário analisar todas as soluções existentes no mercado e, principalmente, encontrar os principais pontos a serem aprimorados e definir a direção a seguir para se inovar uma solução já avançada. Os resultados obtidos apresentam uma solução robotizada onde foi possível aumentar a automatização das operações dos sistemas de armazenamento e melhorar a capacidade de resposta do sistema, levando esta solução para um novo patamar

Shock Generation and Control Using DBD Plasma Actuators

This report is the final report of a NASA Phase I SBIR contract, with some revisions to remove company proprietary data. The Shock Boundary Layer Interaction (SBLI) phenomena in a supersonic inlet involve mutual interaction of oblique shocks with boundary layers, forcing the boundary layer to separate from the inlet wall. To improve the inlet efficiency, it is desired to prevent or delay shock-induced boundary layer separation. In this effort, Innovative Technology Applications Company (ITAC), LLC and the University of Notre Dame (UND) jointly investigated the use of dielectric-barrier-discharge (DBD) plasma actuators for control of SBLI in a supersonic inlet. The research investigated the potential for DBD plasma actuators to suppress flow separation caused by a shock in a turbulent boundary layer. The research involved both numerical and experimental investigations of plasma flow control for a few different SBLI configurations: (a) a 12 wedge flow test case at Mach 1.5 (numerical and experimental), (b) an impinging shock test case at Mach 1.5 using an airfoil as a shock generator (numerical and experimental), and (c) a Mach 2.0 nozzle flow case in a simulated 15 X 15 cm wind tunnel with a shock generator (numerical). Numerical studies were performed for all three test cases to examine the feasibility of plasma flow control concepts. These results were used to guide the wind tunnel experiments conducted on the Mach 1.5 12 degree wedge flow (case a) and the Mach 1.5 impinging shock test case (case b) which were at similar flow conditions as the corresponding numerical studies to obtain experimental evidence of plasma control effects for SBLI control. The experiments also generated data that were used in validating the numerical studies for the baseline cases (without plasma actuators). The experiments were conducted in a Mach 1.5 test section in the University of Notre Dame Hessert Laboratory. The simulation results from cases a and b indicated that multiple spanwise actuators in series and at a voltage of 75 kVp-p could fully suppress the flow separation downstream of the shock. The simulation results from case c showed that the streamwise plasma actuators are highly effective in creating pairs of counter-rotating vortices, much like the mechanical vortex generators, and could also potentially have beneficial effects for SBLI control. However, to achieve these effects, the positioning and the quantity of the DBD actuators used must be optimized. The wind tunnel experiments mapped the baseline flow with good agreement to the numerical simulations. The experimental results were conducted with spanwise actuators for cases a and b, but were limited by the inability to generate a sufficiently high voltage due to arcing in the wind-tunnel test-section. The static pressure in the tunnel was lower than the static pressure in an inlet at flight conditions, promoting arching and degrading the actuator performance