A day at the hospital

Last week I was invited to attend in a knee surgery at the Hospital Cavale Blanche, in Brest. For my PhD project, the research work that I am currently carrying on is actually closer to the mechanical side of Robotics (microactuators, tiny mechanical structures, wireless energy transfer techniques 
). Although, since one of my supervisors is an orthopedic surgeon, I was invited to participate to TKA surgery. Basically, this meant two things: I had to put on specific sterilized clothes and, once in the operating room, I was allowed to watch and put questions 🙂

When I got here I was told that, for PhD students in the field of Robotic Surgery, half a day at the hospital was more useful, in terms of acquirable knowledge, than a month of theoretical study. Actually, one of the aspects I mostly appreciated was the “pedagogical approach” of the surgeon towards the observers. We were two, a sweet girl who’s completing her studies in Pharmacology and me. And the surgeon kept explaining each single step, motivating each procedure and answering all our questions. The confidence he showed while (literally) manipulating the patient’s knee and conducting the operation in front of younger and less experienced surgeons was simply amazing.

Before the surgery, the patient can decide to undergo either general or local anesthesia. Let’s say that the noises and, especially, the smells produced by hammers and saws are not the best way to stimulate one’s appetite 😉 But one thing is sure: after living the atmosphere of such a delicate surgical operation, and understanding that one can really trust expert surgeons, personally I wouldn’t be so worried/scared to undergo TKA as I was before 🙂

the Meniscus: some hints

Medically speaking, the “cartilage” is actually known as the meniscus. The meniscus is a C-shaped piece of fibrocartilage which is located at the peripheral aspect of the joint. The majority of the meniscus has no blood supply. For that reason, when damaged, the meniscus is unable to undergo the normal healing process that occurs in most of the rest of the body. In addition, with age, the meniscus begins to deteriorate, often developing degenerative tears. Typically, when the meniscus is damaged, the torn piece begins to move in an abnormal fashion inside the joint.

Because the space between the bones of the joint is very small, as the abnormally mobile piece of meniscal tissue (meniscal fragment) moves, it may become caught between the bones of the joint (femur and tibia). When this happens, the knee becomes painful, swollen, and difficult to move.

The meniscus has several functions:

  • Stability – As secondary stabilizers, the intact meniscii interact with the stabilizing function of the ligaments and are most effective when the surrounding ligaments are intact.
  • Lubrication and nutrition – The meniscii act as spacers between the femur and the tibia. By doing so, they prevent friction between these two bones and allow for the diffusion of the normal joint fluid and its nutrients into the tissue which covers the end of the bone. This tissue is known as articular cartilage. Maintenance of the integrity of the articular cartilage is critical to preventing the development of post-traumatic or degenerative arthritis.
  • Shock absorption – The biconcave C-shaped pieces of tissue known as meniscii (cartilage in non-medical terms) lower the stress applied to the articular cartilage, and thereby have a role in preventing the development of degenerative arthritis.

source: this website

Exposition “Science et Robotique”

L’exposition “Science et Robotique” se dĂ©roulera du 14 Juin au 17 Juin au Cent quatre, 104 Rue d’Aubervilliers, 75019 Paris, http://www.104.fr. Les 2 premiers jours seront des journĂ©es professionnelles et, lors des 2 derniers, l’exposition sera ouverte au grand public.

Vous pourrez y voir des dĂ©monstrations en grandeur nature de systĂšmes robotiques issus des recherches menĂ©es dans les laboratoires et entreprises membres du GdR Robotique (www.gdr-robotique.org) ainsi qu’Ă©changer avec les chercheurs et ingĂ©nieurs en Robotique.

Les systÚmes et technologies robotiques présentés concernent :
–       Le gĂ©oguidage en trois dimensions de chariots automatisĂ©s
–       Les robots mobiles Ă  applications mĂ©dicales
–       Le robot terrestre « R-DISCOVER »
–       Une plateforme multi-capteurs pour l’exploration et la cartographie sĂ©mantique
–       La navigation autonome d’un mini-drone par vision embarquĂ©e
–       La navigation de vĂ©hicules urbains autonomes avec des systĂšmes de localisation bi-camĂ©ra
–       Une tĂȘte binorale de perception
–       Le traitement du signal social pour la robotique personnelle
–       Des technologies bio-inspirĂ©es de l’animal au robot
–       L’imitation des mouvements humains par un robot humanoĂŻde
–       Le robot parallĂšle « Veloce »
–       Le robot d’assistance Ă  la marche « Moonwalker »
–       La manipulation intelligente et la saisie avec la main « Abilis ».

Cette manifestation est organisĂ©e par le GdR Robotique avec le soutien de l’institut INS2I du CNRS.
L’entrĂ©e est libre et gratuite.

Let’s do it Wireless!

Someone pointed me to this very interesting article from electronicdesign.com . It talks about a new technology for wireless energy transfer. Since it’s actually interesting, I just copy it here (contents belong to Scott Davidson).

Wireless Power Charging Systems Span Time and Frequency Domains

The use of magnetic induction as a way to move power from a source to a device is nothing new. It works, it’s efficient, and it’s safe. So why aren’t we all wirelessly charging our mobile phone, tablet, and laptop batteries? Certainly consumers would appreciate the convenience of just placing their smart phone or tablet down somewhere and watching it automatically charge up.
Like most things in the electronics industry, technologies require standards to achieve widespread adoption. For consumers, standards provide the confidence that the technology works and they won’t be locked into a dead end. For the industry, standards lead to the critical mass needed to drive down component costs. Without standards, even promising technologies fail to gain much traction.

At long last, wireless charging appears to be on its way thanks to the Qi (pronounced “chee”) standard published by the Wireless Power Consortium (WPC). Its more than 100 members range from phone vendors to chipmakers to wireless carriers. At the 2012 International CES, more than 75 products and prototypes included Qi technology. A few other wireless power efforts, most notably WiTricity, are in the works. But with its broad industry backing, Qi seems to be the most probable winner, at least in the short term.
For the embedded or systems engineer, this momentum likely means that you should plan on having to implement wireless charging in your designs at some point in the next few years. Initially, the charging of mobile electronic devices will be the most popular application area for wireless power. But there are many other potential applications in medical devices and the industrial and transportation segments. For instance, instead of plugging in electric vehicles, drivers could simply drive into wireless charging bays when they need to juice up.

Unlike wireless telecommunication systems such as radio or cellular phones, wireless power transmission depends more on the efficiency of transfer than signal-to-noise ratio. From a measurement perspective, the chargers present many design challenges.
In its current spec, a Qi wireless charger is designed to produce 5 W of charging power. The efficiency of power transfer depends on system design including both transmitter and receiver, specifically the interaction between each one. Designs typically target greater than 70% efficiency for a 5-W system. The selection of coils, shielding, components, and physical design influence the overall system efficiency.
This is more complicated in a wireless charging system than in a typical charger, since the wireless system requires both a transmitter and a receiver. Other complications exist due to the shielding requirements, which are necessary to protect sensitive electronics and the battery from the RF fields. And, the system must be able to detect foreign objects so they don’t get hot or reduce the system’s efficiency.

A Qi system includes low-frequency modulated RF, digital, and analog circuits all on a single board (see the figure). The charging system uses digital communication for JTAG debugging and to transfer data between the secondary and primary circuits across the resonant link. A secondary-side microcontroller monitors the charger’s output voltage, generates signals, and uses modulation techniques to transfer information to the primary side.

The information is demodulated on the primary side, where the primary-side microcontroller interprets it. The modulated information is organized into information packets that have preamble bytes, header bytes, message bytes ,and checksum bytes. Per the WPC specification, information packets can be related to Identification, Configuration, Control Error, Rectified Power, Charge Status, and End of Power Transfer information.
The emergence of wireless power dovetails with another trend in embedded systems: the use of wireless everywhere. More than 60% of oscilloscope users also use a spectrum analyzer. These engineers are troubleshooting embedded system designs with integrated wireless modules, requiring them to work in both the time and frequency domain. This has led to the need for more capable oscilloscopes such as the Tektronix MDO4000 that can provide time-correlated views of analog, data, and RF signals. The MDO4000 is the world’s first oscilloscope with this ability.

Qi designs illustrate the importance of mixed-domain capabilities. When paired with appropriate accessories such as near-field probes and bench power supplies, the mixed-domain oscilloscope (MDO) can monitor digital control signals, track the RF received output with a spectrum view, and show RF amplitude versus time. This allows the designer to see a signal at its point of origin, within the RF link signal, and at the point of receipt across the transmitter winding. It can also measure the analog step load performance of output regulators and evaluate electromagnetic interference (EMI) emissions.
With a strong push from the WPC, it’s a solid bet that cable clutter will be a thing of the past before too long. For engineers tasked with adding wireless battery charging to their designs, the ability to look at time-correlated analog, digital, and RF signals will be critical to efficient troubleshooting of system-level issues. By integrating a mixed-signal oscilloscope with a modern spectrum analyzer, the MDO4000 for the first time delivers that capability. Goodbye wires.