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If you want to learn more about radio telemetry applications and microcontroller programming using the PIC18F series of microcontrollers this book is for you. The design of a radio telemetry based mini weather station is considered as an example system in the book.

Computer. Automation --- microcontrollers --- PIC (peripheral interface controller) --- weerstations --- telemetrie --- Microcontrollers --- Radio telemetry. --- Radio detectors. --- Programming.

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The objective of this master thesis is to provide the RoboCup team of the University of Liège with a locomotion system for their humanoid robot. RoboCup is an international competition, the ultimate goal of which is to built robotic soccer players that would be able to beat the human World Cup champion team in 2050. This task is threefold. First, a locomotion control method has to be chosen. Second, the architecture and design of the method, adapted to our robot, have to be detailed. Third, tests have to be conducted in a simulator.

The approach chosen is biologically inspired and has been created by Tobias Luksch in his PhD thesis “Human-like Control of Dynamically Walking Bipedal Robot”. This method was proposing two locomotion modes: keeping the balance while standing and walking dynamically. In this work, the method is summarized and the adapted architecture is presented. Every elements of the method has been implemented for the first locomotion mode. However, the adaptation for the second locomotion mode does not require a substantial work as the skeleton would be the same as for the first one and a lot of implementation challenges have already been tackled. Then, this stable standing locomotion mode has been implemented in the Blender simulator. The implementation on a simplified model first allows to validate the method. Then, several limitations of the simulator have been encountered for the complete model of the robot. The physics engine does not always behave realistically, and the method would probably give better results in reality, out of the simulation environment.

To conclude, the implementation of the chosen control method has been completed by giving solutions to technical and design challenges. The approach chosen seems very promising after the tests performed on the simple model. Nevertheless, the choice of another simulator is necessary to complete the tests and the implementation of other locomotion modes.

RoboCup --- Controller --- Control method --- robot --- bipedal --- dynamic walking --- humanoid robot --- biological --- locomotion --- simulation --- Ingénierie, informatique & technologie > Sciences informatiques

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Future European regulations imposing large decrease in CO2 emissions force the manufacturers of heavy-duty vehicles to implement innovative solutions to achieve these challenging targets. In this context, waste heat recovery systems represent a suitable solution to exploit thermal energy lost to the ambient by diesel engines. To this end, waste heat recovery by means of an Organic Rankine cycle (ORC) is considered as a promising technology. This thermodynamic bottoming cycle aims to recover thermal power in order to produce electricity on-board, that can be injected into mild-hybrid drivelines.
Volvo Trucks is studying for many years this fuel-saving technology. In the scope of their current project in which this internship takes part, exhaust gases downstream the exhaust after treatment system are exploited as heat source. The heat sink is simply the ambient air, driven towards the condenser placed behind the cab by two fans. A piston expander is used to produce mechanical power, which is in turn converted into electricity to charge a 48V battery of a mild-hybrid truck.
The modelling of an ORC is a major aspect of the system design methodology. Indeed, simulations are used in the early design phase to compare several system architectures and to select the most appropriated working fluid. At a later stage, the plant model can be exploited to design the controller of the ORC system. It is thus essential to develop a precise and efficient model integrating all the components of the Rankine cycle (heat exchangers, expander, pump, etc.) as well as an accurate procedure to compute working fluid properties. In this context, the present work aims to improve the ORC simulation tool developed by Volvo Trucks on Matlab-Simulink.
At first, a new moving boundaries (MB) model of heat exchanger is developed to replace the previous one, based on a finite volumes (FV) approach. This new model is as accurate as the FV model, but it is computationally faster. This robust model takes the form of a Simulink library and is exploited to model the exhaust boiler as well as the air condenser in the complete Rankine system model. It is validated regarding both steady-state and transient simulations. Thanks to this new approach of heat exchanger modelling, the computational time required to perform simulations of the ORC during a road driving cycle is drastically reduced (-72%).
Secondly, this master thesis is dedicated to the modelling of the lubricant added to the working fluid performing the Rankine cycle. This oil is needed in practice to ensure the lubrication of the piston expander, but its presence was neglected up to now in the Rankine simulation tool where pure working fluid properties are assumed. However, a brief literature review shows that it could have a significant impact on ORC performances. To this end, an empirical solubility model is exploited to compute thermodynamic properties of the mixture composed of working fluid (cyclopentane) and Polyalkylene Glycol (PAG) synthetic oil. In addition, all the components of the Rankine model are revised to take into account the presence of lubricant. This study concludes that the net ORC power is clearly impacted by the presence of lubricant. This decrease in net power depends on the exhaust conditions, the ambient air temperature and the oil circulation rate.

waste heat recovery --- organic Rankine cycle --- automotive --- modelling --- heat exchanger --- moving boundaries --- heat transfer --- PID controller --- lubricant --- solubility model --- Ingénierie, informatique & technologie > Ingénierie mécanique

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Thales Alenia Space is a company producing electronic equipment for space vehicles. In regards to the cost of space programs, the reliability is a main concern. Thus, their products are intensively tested to ensure the long-term performance.
Thales Alenia Space is a reference producer of power supply for Traveling-Wave Tube Amplifier (TWTA). The TWTA are used in telecommunication to amplify Radio Frequency (RF) electro-magnetic waves. The power supply is tested with a dynamic load made of several collector loads. These collector loads are specially designed to simulate electrically the behaviour of the TWTA.
The goal of this master thesis is to design a collector of the TWTA dynamic load. The collector load acts as a variable current source. Several challenges appear in the design of such a device. The collector load combines high voltage input and power dissipation while a good accuracy in the load current is required.
In order to achieve a collector load that simulates accurately the TWTA, this work starts with the derivation of the specification from the TWTA behaviour. Then, the loading circuit which sinks the current and manages the voltage is studied. A control feedback circuit is designed to regulate the current in the loading circuit. High voltage isolation is considered to ensure safety while providing power dissipation.
In this work, a prototype was built to verify the collector load design. Several tests were performed including the current accuracy, control bandwidth and other technical considerations. Finally, the results and improvements are discussed.

TWTA --- Active load --- TWT --- Lead-lag compensation --- analog controller --- High voltage --- current source --- High voltage insulation --- Power MOSFET --- Electro-thermal Instability --- Ingénierie, informatique & technologie > Ingénierie électrique & électronique