WindBots: A Concept for Persistent In-Situ Science Explorers for Gas Giants

This report summarizes the study of a mission concept to Jupiter with one or multiple Wind Robots able to operate in the Jovian atmosphere, above and below the clouds - down to 10 bar, for long durations and using energy obtained from local sources. This concept would be a step towards persistent exploration of gas giants by robots performing in-situ atmospheric science, powered by locally harvested energy. The Wind Robots, referred in this report as WindBots (WBs), would ride the planetary winds and transform aeolian energy into kinetic energy of flight, and electrical energy for on-board equipment. Small shape adjustments modify the aerodynamic characteristics of their surfaces, allowing for changes in direction and a high movement autonomy. Specifically, we sought solutions to increase survivability to strong/turbulent winds, and mobility and autonomy compared to passive balloons

Position and singularity analysis of a class of planar parallel manipulators with a reconfigurable end-effector

Parallel robots with configurable platforms are a class of robots in which the end-effector has an inner mobility, so that its overall shape can be reconfigured: in most cases, the end-effector is thus a closed-loop kinematic chain composed of rigid links. These robots have a greater flexibility in their motion and control with respect to rigid-platform parallel architectures, but their kinematics is more challenging to analyze. In our work, we consider n-RRR planar configurable robots, in which the end-effector is a chain composed of n links and revolute joints, and is controlled by n rotary actuators located on the base of the mechanism. In particular, we study the geometrical design of such robots and their direct and inverse kinematics for n = 4, n = 5 and n = 6; we employ the bilateration method, which can simplify the kinematic analysis and allows us to generalize the approach and the results obtained for the 3-RRR mechanism to n-RRR robots (with n > 3). Then, we study the singularity configurations of these robot architectures. Finally, we present the results from experimental tests that have been performed on a 5–RRR robot prototype

Simple Mechanically Reconfigurable Patch Antennas

Reconfigurable antennas form an active subdivision of antenna and communications research primarily targeted at achieving reconfigurability in the RF, microwave, and millimeter-wave frequency regimes. Mechanical, all-electronic, material based, and optical methods are the most common approaches to achieve reconfigurability. Each method can overlap to create new and innovative approaches to enable device tunability. The sub-class of reconfigurable antennas are antennas that dynamically achieve an adaptable transformation of their frequency, radiation-pattern, polarization, and/or bandwidth characteristics to enable multiple dynamic functionalities. In this thesis, we designed new rectangular and triangular microstrip patch array antennas operating in the 5G midband at 5GHz. These patch antennas were designed and inspired by the Yagi-Uda antenna, where the driven and passive director or parasitic patches are the main elements. It was found that by increasing the number of parasitic elements, the antenna’s gain can be improved, despite some impedance mismatch. The triangular patch array with the best result was then selected to further investigate its reconfigurability capability using two simple mechanically reconfigurable approaches, i.e., 1) single-plane and 2) double-plane patch arrays, focusing on the radiation pattern, gain, and operating frequency, and other antenna performances. The single-side and double-side folded structures were examined in both approaches, while the folded feeding line and curvature folded substrate were also studied in the single-plane patch array. The results provided clear evidence that by folding the substrate at varying angles one can effectively manipulate the antenna\u27s radiation pattern, gain, and center operating frequency location. The impact varies with the degree of folding, signifying a direct relationship between the folding angle and the returning loss or S11 value. Three proposed microstrip array antennas, i.e., the single-plane patch antenna array, the triangle microstrip array, and the microstrip Yagi-Uda antenna array, were fabricated and tested. The simulation and measurement results are in good agreement

A Drone with Insect-Inspired Folding Wings

Flying robots are increasingly adopted in search and rescue missions because of their capability to quickly collect and stream information from remote and dangerous areas. To further enhance their use, we are investigating the development of a new class of drones, foldable sensorized hubs that can quickly take off from rescuers’ hands as soon as they are taken out of a pocket or a backpack. With this aim, this paper presents the development of a foldable wing inspired by insects. The wing can be packaged for transportation or deployed for flight in half a second with a simple action from the user. The wing is manufactured as a thick origami structure with a foldable multi-layer material. The prototype of the foldable wing is experimentally characterized and validated in flight on a mini-drone

Structural analysis of a variable-span wing-box

This dissertation describes the work done to analyse the wing-box of a variable-span wing. Based on previous work in the CHANGE project the main objective of this study is the experi-mental analysis of the wing-box structure’s prototype build at Universidade da Beira Interior, one of the CHANGE project partners. Surrounding the preliminary design of this project, a nu-merical model written, concerning a parallel work, was modified and used to analyse the mass and displacement variations according to the moving fraction and semi-span of the morphing wing-box. It was first dimensioned the jig to statically validate this structural model that con-cerns the following work. Through the use of Computer Aided Design tools and numerical cal-culation, it was designed and built an experimental setup. Based on computational structural analysis tools, the numerical model allowed the parametric study of the preliminary wing-box design comprising the mass and displacement changes in accordance of the two following pa-rameters: moving fraction and semi-span. In order to complement this study, various configu-rations of the preliminary wing-box were analysed such as the reduction of the composite sand-wich skin’s thickness. With the help of programming tools two polynomial functions were cal-culated from the respective variations previous described. Finally, experimental tests were performed on the prototype of the preliminary wing design. The numerical model was validated and the values are in good agreementEsta dissertação de mestrado descreve o trabalho realizado para analisar a estrutura da caixa de torção de uma asa de envergadura variável. Com base no trabalho realizado anterior-mente no projeto CHANGE o principal objetivo desta dissertação é a validação do modelo nu-mérico, feito por Pedro Santos, da caixa de torção envolvente no desenho preliminar para este projeto. Primeiramente foi dimensionado o estaleiro para validar estaticamente este modelo estrutural em que se constituiu o seguinte trabalho. Através do uso de ferramentas computaci-onais de desenho (CAD) e cálculo numérico, foi projetada e construída a montagem experimen-tal. Com base em ferramentas de análise estrutural computacional, o modelo numérico permi-tiu o estudo paramétrico, um dos objetivos deste trabalho. De modo a complementar este estudo, foram analisadas várias configurações da asa preliminar para compreender a variação do peso da estrutura e da flexão de acordo com a fração da envergadura móvel. Com a ajuda de ferramentas de programação obtiveram-se dois polinómios calculados a partir das respetivas variações anteriormente descritas. Finalmente foram feitos testes experimentais no protótipo do desenho da asa preliminar.

Type synthesis and static balancing of a class of deployable mechanisms

This thesis addresses the type synthesis and static balancing of a class of deployable mechanisms, which can be applied in applications in many areas including aerospace and daily life. Novel construction methods are proposed to obtain the deployable mechanisms. First, the type synthesis of the foldable 8-revolute joint (R) linkages with multiple modes is presented. Two types of linkages are constructed by connecting planar 4R linkages and spherical 4R linkages. The obtained linkages can be folded into two layers or four layers, and have multiple motion modes. A spatial triad is also adopted to build single-loop linkages, then the single-loop linkages are connected using spherical (S) joints or RRR chains to obtain deployable polyhedral mechanisms (DPMs). The DPMs have only 1- degree-of-freedom (DOF) when deployed, and several mechanisms with 8R linkages and 10R linkages have multiple motion modes and can switch modes through transition positions. In addition, when connecting single-loop linkages using half the number of the RRR chains, the prism mechanisms obtain an additional 1-DOF rotation mode. Furthermore, the DPMs are developed into statically balanced mechanisms. The geometric static balancing approaches for the planar 4R parallelogram linkages, planar manipulators, spherical manipulators and spatial manipulators are developed so that the mechanisms can counter gravity while maintaining the positions of the mechanisms. Only springs are used to design the statically balanced system readily, with almost no calculation. A novel numerical optimization approach is also introduced which adopts the sum of squared differences of the potential energies as the objective function. Using the proposed static balancing approaches, the 8R linkages and the DPMs presented in this thesis can be statically balanced

Final design proposal: Delta Group-Nood Rider 821(tm)

The Nood Rider 821 (trademark) twin-engine, prop passenger aircraft is described. It is argued that the aircraft is very economical to operate and maintain, offering competitive advantages in the air travel marketplace. The aircraft was designed to operate in 'Aeroworld', a fictional world where the passengers are ping pong balls and the distances between cites are on the order of thousands of feet

Optimization of the 2PRU-1PRS Parallel Manipulator Based on Workspace and Power Consumption Criteria

In the last few years, parallel manipulators are being increasingly studied and used for different applications. The performance of parallel manipulators is very sensitive to the geometric parameters, so it is essential to optimize them in order to obtain the desired function. We propose two optimization algorithms that consider the size and regularity of the workspace. The first one obtains the geometric parameters combination that results in the biggest and most regular workspace. The second method analyzes the geometric parameters combinations that result in an acceptable size of the workspace—even if it is not the biggest one—and finds out which ones result in the lowest power consumption. Even if the results vary depending on the application and trajectories studied, the proposed methodology can be followed to any type of parallel manipulator, application or trajectory. In this work we focus on the dimension optimization of the geometric parameters of the 2PRU-1PRS Multi-Axial Shaking Table (MAST) for automobile pieces testing purposes.This research was funded by the Regional Government of the Basque Country (IT949-16) and the Science and Innovation Ministry of the Spanish Government (PID2019-105262RB-I00)

Technology for large space systems: A special bibliography with indexes

This bibliography lists 460 reports, articles, and other documents introduced into the NASA scientific and technical information system between January 1, 1968 and December 31, 1978. Its purpose is to provide helpful information to the researcher, manager, and designer in technology development and mission design in the area of the Large Space Systems Technology (LSST) Program. Subject matter is grouped according to systems, interactive analysis and design, structural concepts, control systems, electronics, advanced materials, assembly concepts, propulsion, and flight experiments