Control of flexible joint robotic manipulator using tuning functions design

The goal of this thesis is to design the controller for a single arm manipulator having a flexible joint for the tracking problem in two different cases. A controller is designed for a deterministic case wherein the plant parameters are assumed to be known while another is designed for an adaptive case where all the plant parameters are assumed to be unknown. In general the tracking problem is; given a smooth reference trajectory, the end effector has to track the reference while maintaining the stability. It is assumed that only the output of the manipulator, which is the link angle, is available for measurement. Also without loss of generality, the fast dynamics, that is the dynamics of the driver side of the system are neglected for the sake of simplicity; In the first case, the design procedure adopted is called observer backstepping. Since the states of the system are unavailable for measurement, an observer is designed that estimates the system states. These estimates are fed to the controller which in turn produces the control input to the system; The second case employs a design procedure called tuning functions design. In this case, since the plant parameters are unknown, the observer designed in case one cannot be used for determining the state estimates. For this purpose, parameter update laws and filters are designed for estimation of plant parameters. The filters employed are k-filters. The k-filters and the parameter update laws are given as input to the controller, which generates the control input to the system; For both cases, the mathematical models are simulated using Matlab/Simulink, and the results are verified

A compact switching mode class-f power amplifier design

Even though there had been extensive research in Switching Mode Power Amplifier design their applications at industry level are quite limited. This is because a Fully-Integrated Switching Mode Power Amplifier using conventional active devices such as Bipolar Junction Transistors (BJT) or Metal Oxide Semiconductor Field Effect Transistor (MOSFET) is challenging due to the inherent design challenges in the Switching Power Amplifier design. A Fully-Integrated Differential Class-F2,3 Power Amplifier design is explored for this Thesis research. This Power Amplifier has a maximum theoretical efficiency of 90.7% but this value is reduced because of the switching nature of the active device, parasitic effects associated with layout and the quality factor of the passive components used. Waveform shaping required for a Class-F Power Amplifier is done using the stray inductances within a non-ideal transformer instead of individual inductors. This techniques effective reduces the foot prints of two inductors for the tuning network design and make a Fully-Integrated solution more practical.M.S

Inhibition of Parasitic Farnesyl Diphosphate Synthase: Structural and Thermodynamic Studies

Farnesyl diphosphate synthase (FPPS) is an essential enzyme involved in the biosynthesis of sterols (cholesterol in humans, and ergosterol in yeasts, fungi and trypanosomatid parasites) as well as in protein prenylation. It is inhibited by bisphosphonates, a class of drugs used in humans to treat diverse bone-related diseases. Development of bisphosphonates as anti-parasitic compounds targeting ergosterol biosynthesis has become an important route for therapeutic intervention. As part of my doctoral studies, I determined the X-ray crystallographic structures of complexes of the FPPS from Leishmania major (the causative agent of cutaneous leishmaniasis) with three bisphosphonates, at resolutions of 1.8 Å, 1.9 Å and 2.3 Å. Two of the inhibitors, 1-(2-hydroxy-2,2-bis-phosphono-ethyl)-3-phenyl-pyridinium (300B) and 1-(2,2-bis-phosphono-ethyl)-3-butyl-pyridinium (476A), co-crystallize with the homoallylic substrate, isopentenyl diphosphate (IPP), and 3 Ca2+ ions. A third inhibitor 3-fluoro-l-(2-hydroxy-2,2-bis-phosphono-ethyI)-pyridinium (46I), was found to bind two Mg2+ ions but not IPP. Calorimetric studies showed that binding of the inhibitors is entropically driven. Comparison of the structures of LmFPPS and human FPPS provides new information for the design of bisphosphonates that will be more specific for LmFPPS inhibition. The structure of the LmFPPS-46I homodimer shows that binding of the allylic substrate to both monomers of the dimer results in an asymmetric dimer with one open and one closed homoallylic site. We propose that IPP binds first to the open site that then closes, opening the site on the other monomer that closes after binding the second IPP leading to the symmetric, fully occupied FPPS dimer observed in other structures. Linear 2-alkylaminoethyl-1,1-bisphosphonates are effective agents against proliferation of Trypanosoma cruzi--the etiologic agent of American trypanosomiasis (Chagas disease)-- exhibiting IC50 values in the nanomolar range against the parasites. This activity is associated with inhibition at the low nanomolar level of the T. cruzi farnesyl diphosphate synthase (TcFPPS). X-ray structures and thermodynamic data of the complexes TcFPPS with five compounds of this family show that the inhibitors bind to the allylic site of the enzyme with their alkyl chain occupying the cavity that binds the isoprenoid chain of the substrate. The compounds bind to TcFPPS with unfavorable enthalpy compensated by a favorable entropy that results from a delicate balance between two opposing effects: the loss of conformational entropy due to freezing of single bond rotations, and the favorable burial of the hydrophobic alkyl chains. The data suggest that introduction of strategically placed double bonds and methyl branches should increase affinity substantially

Effects of Bass Guitar Pickups on Pitch Detection and Pitch Shifting

The thesis work aimed to study the effects bass guitar pickups produce when the signal is pitch-shifted or detected for synthesis. Due to the significant role a pickup plays in the sonic qualities of a stringed electric instrument, it is vital to understand the effects it yields when the signal is subject to pitch tracking or alteration algorithms. The main goal of the study was to aid Darkglass Electronics, a Finnish bass accessory manufacturer, in developing embedded effects for bass guitars without any compromise in sonic quality. Using data analytics programming languages such as Python, a correlation and analysis tool was developed. Data points were collected from using an audio signal with the algorithms and compared to the ideal application. The script determined and flagged deviations and errors, which led to further investigation for the cause and suggested potential improvements. To perform tests on the pickup types, a bass guitar was modified to contain a humbucker pickup and a piezo bridge pickup. A debugging pre-amplifier was designed for the bass guitar to encompass signals from both pickups using Altium - an ECAD software. The results of the tests concluded that the piezo pickup produced effects that were undesirable for the Darkglass DSP application of the pitch detection and shifting algorithms. Furthermore, the harmonic content analysis determined the fundamental difference between the pickup types. Although the piezo produced the most errors, various applications where the piezo would be a viable choice were also discovered

Inhibition of Parasitic Farnesyl Diphosphate Synthase: Structural and Thermodynamic Studies

Farnesyl diphosphate synthase (FPPS) is an essential enzyme involved in the biosynthesis of sterols (cholesterol in humans, and ergosterol in yeasts, fungi and trypanosomatid parasites) as well as in protein prenylation. It is inhibited by bisphosphonates, a class of drugs used in humans to treat diverse bone-related diseases. Development of bisphosphonates as anti-parasitic compounds targeting ergosterol biosynthesis has become an important route for therapeutic intervention. As part of my doctoral studies, I determined the X-ray crystallographic structures of complexes of the FPPS from Leishmania major (the causative agent of cutaneous leishmaniasis) with three bisphosphonates, at resolutions of 1.8 Å, 1.9 Å and 2.3 Å. Two of the inhibitors, 1-(2-hydroxy-2,2-bis-phosphono-ethyl)-3-phenyl-pyridinium (300B) and 1-(2,2-bis-phosphono-ethyl)-3-butyl-pyridinium (476A), co-crystallize with the homoallylic substrate, isopentenyl diphosphate (IPP), and 3 Ca2+ ions. A third inhibitor 3-fluoro-l-(2-hydroxy-2,2-bis-phosphono-ethyI)-pyridinium (46I), was found to bind two Mg2+ ions but not IPP. Calorimetric studies showed that binding of the inhibitors is entropically driven. Comparison of the structures of LmFPPS and human FPPS provides new information for the design of bisphosphonates that will be more specific for LmFPPS inhibition. The structure of the LmFPPS-46I homodimer shows that binding of the allylic substrate to both monomers of the dimer results in an asymmetric dimer with one open and one closed homoallylic site. We propose that IPP binds first to the open site that then closes, opening the site on the other monomer that closes after binding the second IPP leading to the symmetric, fully occupied FPPS dimer observed in other structures. Linear 2-alkylaminoethyl-1,1-bisphosphonates are effective agents against proliferation of Trypanosoma cruzi--the etiologic agent of American trypanosomiasis (Chagas disease)-- exhibiting IC50 values in the nanomolar range against the parasites. This activity is associated with inhibition at the low nanomolar level of the T. cruzi farnesyl diphosphate synthase (TcFPPS). X-ray structures and thermodynamic data of the complexes TcFPPS with five compounds of this family show that the inhibitors bind to the allylic site of the enzyme with their alkyl chain occupying the cavity that binds the isoprenoid chain of the substrate. The compounds bind to TcFPPS with unfavorable enthalpy compensated by a favorable entropy that results from a delicate balance between two opposing effects: the loss of conformational entropy due to freezing of single bond rotations, and the favorable burial of the hydrophobic alkyl chains. The data suggest that introduction of strategically placed double bonds and methyl branches should increase affinity substantially

On the discrete generalized Lyapunov equation

In this paper we study the discrete generalized Lyapunov equation for implicit systems. We show how the anticipation phenomenon and the asymptotic stability of the system can be studied in terms of the solutions to the discrete generalized Lyapunov equation. We further study under which conditions these solutions are unique. Numerical examples are provided to illustrate the results presented. © 1995

Design, synthesis, calorimetry, and crystallographic analysis of 2-alkylaminoethyl-1,1-bisphosphonates as inhibitors of trypanosoma cruzi farnesyl diphosphate synthase

Linear 2-alkylaminoethyl-1,1-bisphosphonates are effective agents against proliferation of Trypanosoma cruzi, the etiologic agent of American trypanosomiasis (Chagas disease), exhibiting IC 50 values in the nanomolar range against the parasites. This activity is associated with inhibition at the low nanomolar level of the T. cruzi farnesyl diphosphate synthase (TcFPPS). X-ray structures and thermodynamic data of the complexes TcFPPS with five compounds of this family show that the inhibitors bind to the allylic site of the enzyme, with their alkyl chain occupying the cavity that binds the isoprenoid chain of the substrate. The compounds bind to TcFPPS with unfavorable enthalpy compensated by a favorable entropy that results from a delicate balance between two opposing effects: the loss of conformational entropy due to freezing of single bond rotations and the favorable burial of the hydrophobic alkyl chains. The data suggest that introduction of strategically placed double bonds and methyl branches should increase affinity substantially.Fil: Aripirala, Srinivas. University Johns Hopkins; Estados UnidosFil: Szajnman, Sergio Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; ArgentinaFil: Jakoncic, Jean. National Synchrotron Light Source; Estados UnidosFil: Rodriguez, Juan Bautista. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; ArgentinaFil: Docampo, Roberto. University of Georgia; Estados UnidosFil: Gabelli, Sandra B.. University Johns Hopkins; Estados UnidosFil: Amzel, L. Mario. University Johns Hopkins; Estados Unido