Undergraduate research

iPad jako operátorská konzole pro planární manipulátor

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Cílem projektu je vytvořit uživatelské rozhraní pro řízení planárního manipulátoru pomocí tabletu iPad. Práce by se týkala dvou různých manipulátorů, které se principálně liší ale v některých aspektech jsou podobné. Jednak jde o manipulátoru, který je založený na tzv. dielektroforéze, a druhý, který využívá tzv. magnetoforézu. V prvním případě se pomocí sady mikroelektrod vytváří a tvaruje elektrické pole, které dovoluje pohybovat s miniaturními objekty o velikosti jednotek až desítek mikrometrů. Ve druhém případě se využívá matice elektromagnetů pro vytváření magnetického pole, které pohybuje s jednou nebo několika kovovými kuličkami s rozměrem o několik řádů větším (jednotky milimetr).

Uživatelské rozhraní by jednak poskytovalo operátorovi informaci o aktuálním stavu platformy, především tedy zobrazení aktuální polohy jednotlivých objektů ať už pomocí promítnutí obrazu z kamery snímající akční prostor, nebo pomocí grafické vizualizace. Dále by rozhraní dovolovalo zadávat cílové polohy a dráhy pro jednotlivé objekty pomocí dotyků. Součástí práce by byla i realizace propojení mezi uživatelským rozhraním na tabletu a samotným manipulátorem. iPad by buď komunikoval s PC, na kterém by běžel program ovládající platformu, nebo by se iPad připojil přímo k manipulátoru pomocí bezdrátové sítě, či přes systémový konektor.

Výhodou pro řešení projektu je předchozí znalost jazyka Object C a vlastnictví počítače Mac s procesorem Intel. Ani jedno však není nutnou podmínkou. iPad pro ladění bude k dispozici.

Evaluation of methods for measurement of a position on a planar surface

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The goal of this student project is to investigate and evaluate several methods for measurement of a position of a single or multiple objects in a small planar arena (say, up to 1m2). The task is motivated by the currently ongoing research in planar feedback manipulation such as positioning an iron ball on top of a rectangular array of electromagnets.   

The particular list of methods that should be studied, evaluated and compared is:

  • processing the images taken by a camera observing the global scene (from above)
  • resistive foil
  • LED matrix
  • set of IR sensors
  • capacitive sensors
  • magnetic sensors

The task needs a creative student with some modest hobby-level skills in electronics. These could be developed while working on the project, of course. The willingness to learn these hardware oriented skills is crucial.

As a continuation of this task, some development of algorithms for the chosen hardware platform is expected.

Contact person: 
Jiří Zemánek

Using state estimator methodologies for data processing - summer internship at LMS International, Leuven, Belgium

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One of our industrial partners - LMS International, a hi-tech company located in Leuven, Belgium - is offering summer internships to top students from the fields of control and automation. The exact period is negotiable but the position should last at least three months. LMS will offer a small apartment in their own dormitory (just next to their facilities) not far from the center of the historial city of Leuven. On top of that, LMS will pay a monthly living allowance of 250 Euro. LMS hosts a lot of foreign students and they are housed in the same building, therefore, a lot of new contacts with people from all around the world will be certainly made. The work started during the proposed started internship can be turned into a graduate project assignment on a supervision of which researchers both from LMS and from AA4CC will collaborate.

Technical problem description: The flexibility of a car body has an influence on vehicle dynamics. The importance of the flexibility of the body during handling maneuvers has already been shown. Full vehicle multibody models are widely used to improve handling and ride comfort performances of passenger cars. However, when focusing on body, it is difficult to validate the simulation results as the forces at the body/suspension interface cannot be measured.

LMS has a unique test-based technology to identify the individual forces acting in the suspension-to-body connection points and to visualize the body-deformation during handling maneuvers. The body force identification is based on strain data. The frequency range of interest is between 0 and 5 Hz. Strain-gauges are capable of accurately measuring the quasi-static body-deformation while the signals are not saturated by rigid-body DC behavior (as would be the case when DC-accelerometers are used). To identify all suspension-to-body forces a large number of strain-gauges is required to achieve enough over-determination for the inverse method for force-estimation. The strain data are measured with a dynamic measurement system (Scadas Mobile 200 channel system). The time-domain body-forces are identified using an inverse methodology. The method requires transfer functions from force-input in the suspension connections to the strain-responses on the body. These transfer functions are measured in trimmed-body condition and represent the calibration of the forces acting on the body relative to the measured strain. Once these transfer functions are measured. The car is brought in its original conditions and road tests are performed, where dedicated maneuvers either with a test pilot or test robot are performed. With the measured operational strain and the strain-over-force transfer functions the time-domain forces can be estimated using matrix inversion.

The procedure that will be investigated will first compute an initial guess of the suspension forces based on the matrix inversion method that has been used in the past. To improve the accuracy, the obtained force time series are applied to a mathematical model of the car, which calculates accelerations on the body of the car. During the operational measurements with the strain gauges, also accelerations on the same locations as in the mathematical model are recorded. Accelerometer instrumentation is a much easier process then strain gauges. Based on the differences between the measured accelerations and the ones computed by the model, corrections on the initial suspension forces are calculated. The latter will be performed based on methodologies from the control community, called state estimation methodologies. The most well-known state estimator is the Kalman filter. More advanced methods are extended Kalman filter, unscented filter, grid based methods, particle filter, moving horizon estimator, …

In this thesis, a study will be performed on a CAE model to determine good sensor locations (observability of the body forces). The whole procedure will be tested on a CAE model. Also experimental data will be put available

Contact person: 
Zdeněk Hurák

State estimation on a gear box test set-up - summer internship at LMS International, Leuven, Belgium

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One of our industrial partners - LMS International, a hi-tech company located in Leuven, Belgium - is offering summer internships to top students from the fields of control and automation. The exact period is negotiable but the position should last at least three months. LMS will offer a small apartment in their own dormitory (just next to their facilities) not far from the center of the historial city of Leuven. On top of that, LMS will pay a monthly living allowance of 250 Euro. LMS hosts a lot of foreign students and they are housed in the same building, therefore, a lot of new contacts with people from all around the world will be certainly made. The work started during the proposed started internship can be turned into a graduate project assignment on a supervision of which researchers both from LMS and from AA4CC will collaborate.

Technical problem description:LMS has a set-up to test gear boxes. Several quantities can be measured such as, input speeds and torques but also electrical quantities of the motors that propel or brake the shafts of the gear box. The idea is to combine this information to obtain a good estimate about the input and output power of the gear box. Knowledge of gearboxes, electrical motors and Kalman filtering is a plus. Ability to perform theoretical studies as well as practical experiments. The estimator should be implemented on a rapid control development platform. This will be a Xenomai based platform.

 

 

Contact person: 
Zdeněk Hurák

Distribuovaná ultrazvuková lokalizace mobilních senzorických uzlů

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Cílem projektu je navržení systému pro distribuovanou lokalizaci mobilních senzorických uzlů s využitím ultrazvukových přijímačů a vysílačů. Jádro práce bude spočívat ve vývoji algoritmů a jejich implementaci a experimentálním ověřování.

Motivací pro vývoj takového systému je výzkum v mobilní robotice včetně bezpilotních létajících prostředků, a to zejména těch velmi malých a velmi levných. V současnosti je na pracovišti zadavatele vyvíjena miniaturní quadkoptéra pro indoor použití, projekt je nazván NanoQuad, rozpětí ramen je cca 10cm. Na konci každého ramene bude umístěn ultrazvukový přijímač.

Zadavatel projektu poskytne (jím) zvolené ultrazvukové přijímač(e) i vysílač(e) i rádiovou komunikační jednotku(-y). Bude i vysvětlena základní algoritmická idea pro určování vzdálenosti i směru spočívající v měření zpoždění ultrazvukového signálu oproti rádiovému, a vzájemných zpoždění na jednotlivých přijímačích nesených na různých částech uzlu (například ramenech quadkoptéry). Očekávaným výstupem budou zdokumentované algoritmy, jejich implementace, a záznamy z experimentálního ověřování.

Na práci započatou v tomto týmovém projektu bude možno navázat nejen až v rámci individuálního a diplomového projektu, ale už i nadcházejícím létě formou placené letní stáže na pracovišti zadavatele http://aa4cc.dce.fel.cvut.cz/.

Contact person: 
Zdeněk Hurák

Modeling and distributed control of an array magnetic manipulator

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The task is to build a mathematical (simulation) model of a planar (electro)magnetic manipulator used to steer one or several iron balls in plane (the balls move by rolling, not by levitation). Such manipulator has already been built and it consists of a rectangular array of special modules, each consisting of a 2x2 electromagnets (coils with an iron core) and including the necessary amplifiers and microcontrollers (ARM Cortex M3) and communication circuits (RS485). Currently available are 4 modules, offering to build a 2x2 array of modules, hence 4x4 array of coils. See the attached photo and video or come and see it in our lab.

The manipulator is intended to be used to test various distributed control/manipulation strategies. The experiment can be viewes as an extension  of the popular ball and plate laboratory model, here the plate can be "deformed" locally. Of course, no mechanical deformation is visible, it is just the potential from which the force field is derived that is shaped here.

Whereas another student project is oriented towards finalizing the design of the hardware and working on the firmware, the proposed project aims at a bit more theoretical (or rather computing oriented) part: modeling and model-based control design.

Modeling will be done using Comsol Multiphysics software tool for Finite Element Modeling (FEM) but lumped-system approximation will be searched for to allow for model-based control design. The outcomes of the simulation might also be relevant for possible design modifications and optimizations.

Control design will address several scenarios such as manipulation of a single ball from one position to another (and back) as fast as possible, with no overshoot; following precisely a precomputed trajectory such as the figure eight trajectory; driving two (or more) balls simultaneously so that they come together and then split apart.

Contact person: 
Zdeněk Hurák
Contact person: 
Jiří Zemánek

NIST Mobile Microrobotics Challenge 2012

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We are looking for a good student(s) who will join our research team in participation in the NIST Mobile Microrobotics Challenge 2012 which takes place during 2012 IEEE International Conference on Robotics and Automation in St. Paul, Minnesota, USA, May 14-18, 2012.

All robots entered in the competition must be no bigger than 600 micrometers in their largest dimension and must be able to operate without the direct connection of wires (i.e., untethered operation.) The competition will consist of two events structured to test each microrobot’s speed, agility, and ability to manipulate small objects. Mobility Challenge: Microrobots are required to navigate a planar maze in the shape of a figure eight. Microassembly Challenge: Microrobots must assemble multiple microscale components inside a narrow channel. This task simulates anticipated applications of microassembly, including manipulation within a human blood vessel and the assembly of components in nanomanufacturing. Multiple cooperating microrobots will be allowed.

Our team has been conducting research in the area of planar micromanipulation using dielectrophoresis. It consists in shaping the (gradient of) electric field by applying voltages to properly designed microelectrodes. We feel that our recent desing of a microelectrode array and some control strategies fit perfectly into the scope of this competition. 

The interested student should enjoy competitions, should have some interest in physics and experimental work in notraditional physics and microsystems related domains. The competition takes place in a few months, therefore it is vital to start as soon as possible. The scope of such collaboration can be negotiated. Every little help with the project will be appreciated. Even minor participation in the preparation for this competition will make it easier to participate fully for the next year competion, so do not be afraid to contact us even you feel unsure about the depth and volume of the work. We will certainly tailor our collaboration to your convenience.

In case of succesful research and development, we will do our best to bring the whole team to the place of the final competition - St. Paul, Minnesota, USA, in May 2012.

Contact person: 
Zdeněk Hurák
Contact person: 
Jiří Zemánek

Path planning for a UAV tracking a ground object and using an inertially stabilized camera platform

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Our team has developed several prototypes of inertially stabilized platforms carrying optoelectrical payload such as day and/or night vision cameras, laser range finders and laser  markers. The platforms are intended to be mounted on mobile vehicles, in particular unmanned aerial vehicles (UAV). Together with implementation of HW and SW for these platforms, our group has developed and documented/published a control theoretic framework for this class of control systems. The platforms have been extensively tested indoor but also outdoor. Hence, a certain maturity can be claimed in the mere task of inertial stabilization and visual tracking.

The challenge that we are facing now is to extend the current scheme with the functionality of path planning. The current assignment coming from a defense industry partner is that in order to track the ground object, the only actuators are the motors driving the gimbals. No commands to the autopilor of the UAV were allowed. The path of the UAV was set by some algorithm or human operator. The task for the student involved in this project will be to break this constraint and formulate the problem of planning a path for a UAV in order to guarantee best visual tracking (and inertial stabilization). One and several ground objects will be considered. Moving and fixed.

The ultimate goal is not to come up with a fully autonomous solution. Such a system will not be realistic in the next decade or so for legal reasons. But it may be perfectly realistic and actually quite useful if some optimization problem can be formulated and solved in real time which assist the human operator in planning the right path, which is currently done manually and heuristically. Using numerical real-time optimization, it will be possible to include whatever restrictions on distances to the observed objects, UAV turning radii, but even the UAV wheels constraining the field of view. This way the work has a good chance to be included in a real system.

The interested student should have some inclination towards numerical optimization since the work will revolve around it. But no deep research knowledge of the subject is needed. Being an aerospace enthusiast might make the work more enjoyable too although only basic concepts from aerospace will be needed such as flight angle, roll, pitch and yaw rates and so on.

Contact person: 
Zdeněk Hurák
Contact person: 
Martin Řezáč

Interaktivní svíticí míčky pro žonglování

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Úkolem práce je navrhnout a vyrobit funkční vzorek interaktivní svíticích míčků pro žonglování. Konstrukce míčků by byla postavena na mechanické části komerčního produktu svíticího míčku, která by byla doplněna o nově navrženou a realizovanou elektronikou. Míček by na základě způsobu žonglování vytvářel různé vizuální efekty, např. postupné a skokové změny barev, modulaci intenzity, záblesky, atd. Data o žonglovacím stylu by míček získával z inerciálních senzorů – magnetometry, akcelerometry, gyroskopy – a vyhodnocoval by jednak pomocí odhalování opakujících se vzorů a dále také pomocí detekce řídicích gest.

Obsahem práce je navrhnout a realizovat elektroniku pro zabudování do žonglovacího míčku. Elektronika bude obsahovat mikroprocesor, buzení LED, inerciální senzory a volitelně také modul pro bezdrátovou komunikaci. Dále bude práce orientována na návrh a testování algoritmů pro zpracování dat ze senzorů a jejich převedení v řízení LED. Závěrem by mělo být testování a vytvoření atraktivní video dokumentace.

Contact person: 
Jiří Zemánek

Experimentální platforma pro distribuovanou planární magnetickou manipulaci

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Úkolem této práce je pro účely výzkumu paralelní bezkontaktní manipulace postavit experimentální platformu pro manipulaci pomocí magnetického pole. Distribuovaná manipulace je stále se rozvíjející obor zasahující praktické aplikace, které využívají masivní pole aktuátorů pro pohyb s objekty příkladem je třeba čip s mechanickými MEMS rezonátory pro manipulaci s mikroskopickými objekty či pole všesměrových koleček pro dopravu balíků.

Přistup k řízení těchto systémů, které jsou charakteristické jednak vysokým řádem a také výraznou strukturou, se stále vyvíjí. Kromě simulací je ale užitečné mít k dispozici i testovací fyzické systémy. Jedním takovým může být například soustava elektromagnetů, které budou buzeny proměnným proudem, aby tak tvarovaly magnetické pole v prostoru nad sebou a v důsledku tak pohybovaly s jedním nebo i několika objekty najednou.

Záměrem této práce je především sestavit výše zmíněnou experimentální platformu, jejíž některé části jsou již navrženy. Náplní práce by bylo tedy hlavně programování modulů (každý pro řízení a buzení čtyř elektromagnetů) platformy, sestavení a oživení platformy, návrh řídicího SW, návrh měření polohy objektů a méně prakticky orientovaná část práce by spočívala v návrhu algoritmů pro řízení a simulacích.

Contact person: 
Zdeněk Hurák
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