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Optical path difference active control mechanism
Neumanová, Anna ; Šulc, Václav (referee) ; Špaček, Matěj (advisor)
There is a long-term development of the Coherence-Controlled Holographic Microscope (CCHM) ongoing in the Laboratory of Experimental Biophotonics at the Faculty of Mechanical Engineering in Brno. A mechanism for active control of the optical path length needs to be implemented in the imaging setup of the microscope. The reason is the high sensitivity of the microscope to the optical path difference of~its~optical branches. Therefore, the mechanism must meet the high-resolution requirements. First, suitable mechanisms for this application are compared. Based on the research, three conceptual designs are presented. For the selected design, a complete technical solution is elaborated. The mechanism is then fabricated, assembled and tested in terms of its motion characteristics.
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Active Vibration Damping/Chatter Control of Machine Tool Spindle Units
Škúci, Michal ; Blecha, Petr (referee) ; Březina, Tomáš (advisor)
This bachelor’s thesis describes the issue about machining, causes of spindle chatter and different ways of chatter damping. It evaluates advantages and disadvantages of different ways of damping. There was made and described simple simulation model on which searching simulations was made for purpose of receiving picture of behaviour of model for different parameters. Model of active damping was made too.
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Active control of the wake behind the cylinder
Broučková, Zuzana ; Flídr, Erik ; Šafařík, P. ; Trávníček, Zdeněk
Active control of the flow around a cylinder using synthetic jet (SJ) array was experimentally investigated. The prevailing method was flow visualization. Modification of the wake was investigated at two values of a dimensionless momentum coefficient (Cμ = 0.21 and 1.02). Various α and Cf parameters were tested (where α is the angle between SJs and the main flow direction and Cf is the frequency ratio). The control moves separation point more downstream. Increasing frequency ratio Cf causes refining of the vortex structure. When SJs are placed at the front or rear stagnation points, wake tends towards the symmetrical pattern.
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Active Vibration Damping/Chatter Control of Machine Tool Spindle Units
Škúci, Michal ; Blecha, Petr (referee) ; Březina, Tomáš (advisor)
This bachelor’s thesis describes the issue about machining, causes of spindle chatter and different ways of chatter damping. It evaluates advantages and disadvantages of different ways of damping. There was made and described simple simulation model on which searching simulations was made for purpose of receiving picture of behaviour of model for different parameters. Model of active damping was made too.
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Spectral analysis of continual and synthetic jet
Broučková, Z. ; Trávníček, Zdeněk ; Šafařík, P.
This experimental work deals with a characterization of three types of air jet flows (continual jet, synthetic jet and continual jet which is controlled by a synthetic jet). The characterization is performed using the power spectral density (PSD). All the characteristics were obtained from single-point measurements of flow velocity. The velocity was measured by a hot-wire anemometer (CTA). Power spectral density was acquired directly from measured signal (or from velocity data) by means of MATLAB software. Obtained graphs showed the control effect on the main flow behaviour. The significant qualitative change was revealed near a boundary of synthetic jet formation. Moreover it was concluded that this significant change can be also well quantified.
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Active control of the electromagnet force
Vaněk, František ; Cibulka, Jan ; Kozánek, Jan
The prototype of the active control of electromagnet force with the help of modern insulated gate bipolar transistors in bridge connection excited by the integrating circuit with the overload protection was proposed and verified. The maximal generated force was about 2kN and the circuit efficiency was better than 80%.
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