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In the field of control systems, testbeds are a pivotal step in the validation and improvement of new algorithms for different applications. They provide a safe, controlled environment typically having a significantly lower cost of failure than the final application. Vision systems provide nonintrusive methods of measurement that can be easily implemented for various setups and applications. This work presents methods for modeling, removing distortion, calibrating, and rectifying single and two camera systems, as well as, two very different applications of vision-based control system testbeds: deflection control of shape memory polymers and trajectory planning for mobile robots. First, a testbed for the modeling and control of shape memory polymers (SMP) is designed. Red-green-blue (RGB) thresholding is used to assist in the webcam-based, 3D reconstruction of points of interest. A PID based controller is designed and shown to work with SMP samples, while state space models were identified from step input responses. Models were used to develop a linear quadratic regulator that is shown to work in simulation. Also, a simple to use graphical interface is designed for fast and simple testing of a series of samples. Second a robot testbed is designed to test new trajectory planning algorithms. A templatebased predictive search algorithm is investigated to process the images obtained through a lowcost webcam vision system, which is used to monitor the testbed environment. Also a userfriendly graphical interface is developed such that the functionalities of the webcam, robots, and optimizations are automated. The testbeds are used to demonstrate a wavefront-enhanced, Bspline augmented virtual motion camouflage algorithm for single or multiple robots to navigate through an obstacle dense and changing environment, while considering inter-vehicle conflicts, iv obstacle avoidance, nonlinear dynamics, and different constraints. In addition, it is expected that this testbed can be used to test different vehicle motion planning and control algorithms.

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<p align="justify">Many different active control techniques can be used to control the vibrations of a mechanical structure: they however require at least a sensitive signal amplifier (for the sensor), a power amplifier (for the actuator) and an analog or digital filter (for the controller). The use of all these electronic devices may be impractical in many applications and has motivated the use of the so-called shunt circuits, in which an electrical circuit is directly connected to a transducer embedded in the structure. The transducer acts as an energy converter: it transforms mechanical (vibrational) energy into electrical energy, which is in turn dissipated in the shunt circuit. No separate sensor is required, and only one, generally simple electronic circuit is used. The stability of the shunted structure is guaranteed if the electric circuit is passive, i.e., if it is made of passive components such as resistors and inductors.</p> <p align="justify">This thesis compares the performances of the electric shunt circuits with those of classical active control systems. It successively considers the use of piezoelectric transducers and that of electromagnetic (moving-coil) transducers.</p> <p align="justify">In a first part, the different damping techniques are applied on a benchmark truss structure equipped with a piezoelectric stack transducer. A unified formulation is found and experimentally verified for an active control law, the Integral Force Feedback (IFF), and for various passive shunt circuits (resistive and resistive-inductive). The use of an active shunt, namely the negative capacitance, is also investigated in detail. Two different implementations are discussed: they are shown to have very different stability limits and performances.</p> <p align="justify">In a second part, vibration isolation with electromagnetic (moving-coil) transducers is introduced. The effects of an inductive-resistive shunt circuit are studied in detail; an equivalent mechanical representation is found. The performances are compared with that of resonant shunts and with that of active isolation with IFF. Next, the construction of a six-axis isolator based on a Stewart Platform is presented: the key parameters and the main limitations of the system are highlighted.</p>

Sedimentation in magnetorheological (MR) fluids is undesirable for many technological applications. For this reason, several ways have been proposed to prevent sedimentation instability. This thesis deals specifically with the addition of a suitable additive. The topic was examined based on available literature and according to it was suggested a procedure for the experimental part. Two types of MR liquids with different composition and preparation method were prepared. The first suspensions included a water-in-oil emulsion as a carrier liquid and Span 80 and Tween 80 as additives. For the second MR fluids, the continuous phase was a blend of bearing oils and the suspension was stabilized with organoclay. In both cases, carbonyl iron particles with a diameter of 1,8–2,3 µm were used. The kinetic stability of the prepared MR fluids was monitored and compared using an analytical centrifuge.

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<p align="justify">Many different active control techniques can be used to control the vibrations of a mechanical structure: they however require at least a sensitive signal amplifier (for the sensor), a power amplifier (for the actuator) and an analog or digital filter (for the controller). The use of all these electronic devices may be impractical in many applications and has motivated the use of the so-called shunt circuits, in which an electrical circuit is directly connected to a transducer embedded in the structure. The transducer acts as an energy converter: it transforms mechanical (vibrational) energy into electrical energy, which is in turn dissipated in the shunt circuit. No separate sensor is required, and only one, generally simple electronic circuit is used. The stability of the shunted structure is guaranteed if the electric circuit is passive, i.e. if it is made of passive components such as resistors and inductors.</p><p><p><p align="justify">This thesis compares the performances of the electric shunt circuits with those of classical active control systems. It successively considers the use of piezoelectric transducers and that of electromagnetic (moving-coil) transducers.</p><p><p><p align="justify">In a first part, the different damping techniques are applied on a benchmark truss structure equipped with a piezoelectric stack transducer. A unified formulation is found and experimentally verified for an active control law, the Integral Force Feedback (IFF), and for various passive shunt circuits (resistive and resistive-inductive). The use of an active shunt, namely the negative capacitance, is also investigated in detail. Two different implementations are discussed: they are shown to have very different stability limits and performances.</p><p><p><p align="justify">In a second part, vibration isolation with electromagnetic (moving-coil) transducers is introduced. The effects of an inductive-resistive shunt circuit are studied in detail; an equivalent mechanical representation is found. The performances are compared with that of resonant shunts and with that of active isolation with IFF. Next, the construction of a six-axis isolator based on a Stewart Platform is presented: the key parameters and the main limitations of the system are highlighted.</p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

The master thesis deals with design, manufacturing and testing of a prototype magnetorheological damper developed for Formula Student vehicle. The aim was to design and test the damper with similar damping properties to the vehicle as a conventional damper has. Target force-velocity curves were set using quarter car model and evaluated comparing minimal contact force of a tyre for conventional and newly developed damper characteristics. Structural analysis of designed parts, hydraulic and static magnetic analysis were performed. Manufacturing of a specific part magnetorheological damper part was described – piston. Manufactured prototype damper characteristics were evaluated.

The ASME 2014 Conference on Smart Materials, Adaptive Structures and Intelligent Systems (SMASIS) was held from 8-10 September 2014 in Newport, Rhode Island. The scope of the Conference covers intelligent, flexible, adaptive materials and systems that respond to changes in the environment to perform in the most profitable way. Scientific strides and technological maturity in the field are linked to the interdisciplinary efforts at universities, government and industry. SMASIS aims at assembling world experts across engineering and scientific disciplines such as mechanical, aerospace, electrical, materials, and civil engineering, as well as biology, physics and chemistry, to discuss the latest findings and trends in this fruitful area of research.