Spring 2010



Angle estimation in a PWM stepping motor driver by Kalman filtering


The Equipments Controls and Electronics (ECE) section of the EN-STI group at CERN is working on the development of a PWM stepping motor driver able to ensure high positioning repeatability and low Electro Magnetic Interferences (EMI) with a cable length between driver and motor up to 1 Km.  This driver is supposed to be used for moving beam intercepting devices (i.e. collimators, scrapers, dump) in the CERN accelerators where high positioning accuracy is required and the high radioactive environment imposes to install the drivers far away from the motors.  To improve the positioning repeatability of the motors it is intended to use closed-loop control on the motor’s position.  Nevertheless to increase the driver robustness, reliability and installation easiness a sensor-less approach has been chosen; the angle will be estimated using a Kalman filter. Preliminary studies have been performed on the use of a Kalman Filter but the final implementation configuration is not yet decided.  This project proposes to carry out analytical and simulation studies to assess the impact on the accuracy of the position estimate of different implementation proposals.

This project is carried out in collaboration with EN-STI group at CERN.

MER: Alireza Karimi
Type of project: Master
Contact: Alireza Karimi and Christophe Satzmann
Student: Hamed Shisheh Foroush



Analysis and control of instabilities in railway power systems

It is suspected that new customer demands as well as actual control laws for modern railway vehicles could stimulate instabilities and low frequency oscillations in railway power systems. A rigorous analysis of these issues is complicated by the complexity of railway power systems.
A first step of this project consists in analysing the nonlinearities and the parameters which induce instabilities and oscillations in the railway power system by considering one traction unit and the railway network. In order to establish the effect on stability due to other vehicles in the railway system the analysis has to be expanded by considering several traction units. On the basis of the obtained results a control strategy has to be developed in order to avoid instabilities.

Prerequisite: Interest in control theory as well as modeling and simulation with MATLAB.

Professor: Roland Longchamp
Type of project: Semester
Contact: Basile Graf and Philippe Mullhaupt
Student: Shuai Hu


Robust nonlinear controller for an active suspension system

This project aims at developing a robust nonlinear controller for an active suspension system for four-wheeled vehicles. Prior to designing the controller, a quarter-car model will be considered. Generally, a suspension is designed in order to minimize the vertical acceleration of the car body for passenger comfort.  In normal cars, this is achieved by using a spring and a damper. However, these components are passive and have limited capabilities. The idea of feedback suspension system is to put an active component (like a hydraulic or pneumatic cylinder or a linear motor) in parallel to usual passive components and to design a controller. Because the passenger weight varies, the controller must take into account these variations. The scope of this project is to (i) develop a simulation platform for the quarter-car model, (ii) design a controller for the quarter-car model, and finally (iii) validate the controller for varying weights.

Dominique Bonvin
Type of project: Semester
Contact: Willson Shibani and Philippe Müllhaupt
Student: Mohammadmehdi Shafizadeh



Optimal control for the treatment of diabetics during physical activity

Persons with Type 1 Diabetes have to almost continuously adapt their therapy and lifestyle to account for situations like meal intakes, exercise, illness, medication or stress. Patients using insulin pumps have the possibility to infuse time-varying continuous profiles. This flexibility is not fully exploited by the most commonly used rules to compensate for the above mentioned situations. In this project, we propose to focus on the exercise situation. It is known that exercise reduces the insulin needs of the patient for a certain period of time. It is also known that this reduction depends on one side on the duration and intensity of the exercise and on the other side on the patient. A model accounting for the effect of physical activity has recently been developed.

The goal of this project is to improve this model and to estimate its parameters using real patient data. This identification should enable the individualization of the method. Eventually, the model coupled to the patient dependent identified parameters will be used to compute optimal insulin recommendations. These recommendations are either insulin or lifestyle recommendations.
This project is carried out in collaboration with a multinational pharmaceutical company.

MER : Denis Gillet
Type of project: Master
Contact: Alain Bock
Student: Felix Huguenin-Virchaux



Identification and control of an active suspension system

The aim of this project is design of a controller for an active suspension system. The controller will be tested on an experimental platform.  The platform consists of three floors (plates) on top of each other. The top and the middle plates are connected with two springs and a tunable damper, and also with DC motor which serves as an actuator for active  suspension. The bottom plate represents road and serves as a source of  vibrations of top plate which are measured by accelerometer (acceleration relative to platform ground). The objective of the project is to identify the model of the system and compute a controller to reject vibrations with narrow-band time-varying frequency. The controller design is based on the identified nonparametric models and gain-scheduling approach developed in the Automatic Control Laboratory of EPFL.

MER: Alireza Karimi
Type of project: Master or semester
Contact: Zlatko Emedji
Student: Gaspard Lugrin




Control of an autonomous unicycle robot

The Laboratoire d’Automatique is developing an autonomous unicycle robot for educational purpose. The system is supposed to stay on vertical position on its single wheel and move along paths. Preliminary studies have been performed in previous projects both in simulation and on a first prototype.

The goal of this project is to improve the design for achieving full energetically autonomy and to implement a controller able to follow predefined paths.

MER : Denis Gillet
Type of project: Semester
Contact: David Ingram and Alain Bock
Student: Daniel Nellen



Modeling and Optimization of Energy Distribution in Urban Waste Incineration



Tridel is a company located in Lausanne that processes urban waste of 144 cities and villages in the Canton de Vaud. Up to 160’000 t/year of waste is burnt in two furnaces, and the generated heat is used to produce overheated steam. Most of this steam is valorized as thermal energy for remote heating of private houses in Lausanne, while the rest drives a turbine to generate electricity.

This project deals with modeling and optimization of the energy distribution stage. The overheated steam obtained at the output of the furnaces can be either (i) stored into high, medium and low pressure tanks before being sent to heat exchangers and used to heat up water, or (ii) sent to the turbine. Since it is thermodynamically more interesting to produce hot water than electricity, the main objective is to meet the customer requirements for hot water at a prescribed temperature. On the other hand, the steam flow rate through the turbine needs to be sufficient to ensure proper turbine operation and produce the electricity needs of the factory. Hence, a compromise is sought between these two objectives. For this purpose, a model of the energy distribution system will be built and validated. Then, for different steam flow rates, the model will help set the pressure levels in the storage tanks in order to maximize energy utilization.

Professor: Dominique Bonvin 
Type of project: Master
Contact: Gregory Francois and Sean Costello
Student: Sylvain Granges



Implementation of a nonlinear controller for the “ball and plate” system

The project aims at implementing the controller developed using the SIM (Successive Invariant Manifold) algorithm for a “Ball and plate” system on an experimental setup. The nonlinear controller developed using SIM assumes the possibility of infinitely large input values and unrestricted tilt angle of the plate. However, in practice, the system has limited input power and the plate tilt angle is restricted due to mechanical constraints. The aim of this project is to develop an experimental setup for the “Ball and plate” system and implement the SIM algorithm on that system. The scope of this project is to (i) develop an experimental platform for the “Ball and plate” system, (ii) implement the SIM control algorithm on the experimental setup, and finally (iii) validate the controller for trajectory tracking.

Professor: Dominique Bonvin
Type of project: Semester
Contact: Willson Shibani and Philippe Müllhaupt
Student: Ali Motamed



Optimal crossing of automated guided vehicles

Electric Automated Guided Vehicles (AGVs) operating on roads have a high potential for reducing CO2 emissions and traffic congestion in intermodality areas. Advanced maneuvering solutions relying on hierarchical control structures and dynamical optimization will lead to an increase in vehicle density and speed.
In this project, preliminary work on optimal crossing using decentralized navigation functions will be extended to take into account vehicles dynamics and energy constraints during coordinated maneuvers. Typically, priority will be given to heavy vehicles with little energy reserve.

MER : Denis Gillet
Type : Master
Contact: Laleh Makarem
Candidate: Gergely Nardai



Optimisation d’installations de chauffage combinées

L’objectif de ce projet est l’optimisation d’installations de chauffage et de production d’eau chaude sanitaire exploitant une combinaison judicieuse de panneaux solaires thermiques et d’une pompe à chaleur comme sources d’énergie dans une maison familiale.

MER : Denis Gillet
Type : Master
Contact: Gene Bunin and Grégory François
Candidate: Romain Vallotton