Spaceflight | EPFL Graph Search

Spaceflight (or space flight) is an application of astronautics to fly objects, usually spacecraft into or through outer space, either with or without humans on board. Most spaceflight is uncrewed and conducted mainly with spacecraft such as satellites in orbit around Earth, but also includes space probes for flights beyond Earth orbit. Such spaceflight operate either by telerobotic or autonomous control. The more complex human spaceflight has been pursued soon after the first orbital satellites and has reached the Moon and permanent human presence in space around Earth, particularly with the use of space stations. Human spaceflight programs include the Soyuz, Shenzhou, the past Apollo Moon landing and the Space Shuttle programs. Other current spaceflight are conducted to the International Space Station and to China's Tiangong Space Station. Spaceflight is used for placing in Earth's orbit communications satellites, reconnaissance satellites, Earth observation satellites, bu

Evaluation and robotic simulation of the glenohumeral joint

Matteo Mancuso

The shoulder is the joint with the largest range of motion in the human body. It is composed of three articulations, the glenohumeral articulation providing about two thirds of its mobility which is, also the most complex and fragile of the three. For this reason, it possesses a particularly complex stabilization mechanism involving a large number of different structures, making it particularly difficult to model, evaluate and treat. Since many structures are involved in the stabilization of this articulation, pathologies affecting any of these elements may compromise the whole stabilization mechanism. In that case, a good understanding of the mechanisms involved, combined with reliable evaluation tools are necessary to provide an effective treatment. At present, different modelling approaches tried to model the phenomenon of glenohumeral instability, but none was able to replicate the whole mechanism reliably. These limitations are particularly problematic during total shoulder replacement surgeries, where the inability to reproduce healthy glenohumeral motions is the main cause of implant failure. The development of a model able to predict the onset of GH instability based on the surgical planning, would greatly improve the general survivor-ship of the implants, and is one of the main goals of this thesis. Additionally, the clinical tools available for the evaluation of the functional outcome are limited. Clinical questionnaires, static apprehension and laxity scores and two-dimensional evaluations of the articular ranges being the instruments used in most situations. Although fast and simple, these instruments are either prone to biases based on patients' interpretation and psychological state or provide only a partial evaluation of the functional limitations. Considering that the main function of the upper limb (composed of the shoulder, arm, elbow and forearm) is to place and orient the hand in space, for the latter to perform a particular action; the reachable space defined as the total volume where the upper limb is able to place the hand, is a feature of great interest. In biomechanical research laboratories, measurements with standard motion capture system enables a more comprehensive and accurate evaluation of the whole upper limb, including the evaluation of its reachable space. Unfortunately, the use of such platforms is generally too complex, expensive and time-consuming for clinical examinations. To this end, the development of new tools able to bring some of the most interesting features recorded in biomechanical laboratories to the clinical context would offer promising new solutions for the functional evaluation of patients and represent the second goal of this thesis. This thesis proposes two original instruments for the evaluation and robotic simulation of the glenohumeral joint. It offers a tool for reproducing physiological forces and motions within the glenohumeral joint, opening new opportunities for the study of glenohumeral instability. At the same time, it also proposes a second instrument allowing to evaluate the functional impairment of a patient's upper limb in an objective and reliable way, extracting information that in the past required the deployment of unrealistic amounts of resources for a clinical examination.

EPFL2020

Atomic Force Microscopy of Biological Systems: Quantitative Imaging and Nanomotion Detection

Petar Stupar

The core of this thesis is the application of different modalities of atomic force microscopy to study living systems. After a brief introduction, quantitative imaging state of the art is presented and the applications for mammalian, plant, bacterial, and yeast cells are reviewed. The same chapter contains research effort about exploring nanomechanical properties of bone cells exposed to conditions that simulate the ones in outer space, in order to investigate the changes in architectural rearrangements of cells during space flight. The next section takes the focus on probing bacterial adhesion sites with an antibody-modified tip, a research important for the understanding of how bacterial cells adhere to the host and establish an infection. Plant cells and their nanomechanical profiles are also covered in the chapter. A large portion of the thesis consists in development of a new nanomechanical sensing technique, and the exploration of its potential applications. The technique is based on the AFM detection method and focuses on transducing small fluctuations that define living systems into a measurable mechanical change in the cantilever. The fact that there is a disproportionate rise in antimicrobial-resistant bacteria and that our lives depend on the new drugs and diagnostic tools to fight them has fueled the first and largest application of the technique â rapid antimicrobial susceptibility resting. Chapter 3 starts with the introduction of the technique, basic principles and guidelines for its use, and continues on potential applications. Proof of principle of the technique is presented, showing experimental results using blind clinical samples of bloodstream infectious agents. A separate section is devoted to investigations concerning slow-growing bacteria and the application of the technique to rapidly determine which antibiotic would best work against them. It then expands on the applications towards detecting metabolic activity of mitochondria and their response to substrates and inhibition. Furthermore, the method has been described as a rapid anti-cancer profiling tool that might pave the way towards a diagnostic platform for personalized medical treatment. The final section of the third chapter contains the current knowledge of the origins of oscillatory movement that governs the nanomotion technique. It presents different hypothesis and results towards exploring them. The thesis ends with a summary of the main ideas and conclusions about the presented work and future perspectives.

EPFL2018

Motor-Primed Visual Attention for Humanoid Robots

Aude Billard, Luka Lukic, José Santos-Victor

We present a novel, biologically inspired, approach to an efficient allocation of visual resources for humanoid robots in a form of a motor-primed visual attentional landscape. The attentional landscape is a more general, dynamic and a more complex concept of an arrangement of spatial attention than the popular "attentional spotlight" or "zoom-lens" models of attention. Motor-priming of attention is a mechanism for prioritizing visual processing to motor-relevant parts of the visual field, in contrast to other, motor-irrelevant, parts. In particular, we present two techniques for constructing a visual "attentional landscape". The first, more general, technique, is to devote visual attention to the reachable space of a robot (peripersonal space-primed attention). The second, more specialized, technique is to allocate visual attention with respect to motor plans of the robot (motor plans-primed attention). Hence, in our model, visual attention is not exclusively defined in terms of visual saliency in color, texture or intensity cues, it is rather modulated by motor information. This computational model is inspired by recent findings in visual neuroscience and psychology. In addition to two approaches to constructing the attentional landscape, we present two methods for using the attentional landscape for driving visual processing. We show that motor-priming of visual attention can be used to very efficiently distribute limited computational resources devoted to the visual processing. The proposed model is validated in a series of experiments conducted with the iCub robot, both using the simulator and the real robot.