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Digital Control of LevitationVallance, Phillip James 05 July 2001 (has links)
Electromagnetic levitation has been commonly researched for the use in ground transit systems. It is ideal for high-speed applications that require low friction. The principle is simple, use electromagnetic force to balance the force imposed by gravity. However, for attractive levitation the system is unstable and nonlinear. Two dominant approaches to this problem have been to use a state feedback control system or a simple linear PID compensated control architecture. State feedback is a well-known control technique, but is complicated to implement and can rely on linearization of the system dynamics. The simple PID control structure is very easy to implement, but can have severe performance degradation in the presence of noise. This system can usually be identified by its large acoustic noise. This is primarily due to the differential term in the controller. This thesis proposes a solution that uses two concepts: Current Command Generation (CCG) and a closed velocity loop.
CCG linearizes the control structure by utilizing the known magnetic properties of the system to convert a desired force to a current for any given air gap. This removes squared command terms from the control structure. This allows for a reliable and predictable implementation of linear feedback control systems.
The PID implementation of an attractive levitation system uses two control loops. The inner loop is a current controller, which receives current commands from the outer position loop. The proposed control architecture uses three loops. The innermost loop is the current controller, which receives current commands for the CCG. The middle loop is a velocity controller, which receives commands from the position (outer most) loop and produces force command output used as inputs to the CCG. The three loops consist of two Proportional Integral (PI) controllers for the current and velocity controllers and a Proportional (P) controller. There is no derivative term, making the proposed solution's performance far less dependent on noise.
This architecture removes the necessity of nonlinear elements in the control architectures and improves noise rejection through the use of the velocity loop. The acoustic noise performance of this system is enhanced by both of these methodologies and is shown in the experimental setup. / Master of Science
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Smart control of electromagnetically driven dosing pumpsKramer, Thomas, Petzold, Martin, Weber, Jürgen, Ohligschläger, Olaf, Müller, Axel 03 May 2016 (has links) (PDF)
Electromagnetically driven dosing pumps are suitable for metering any kind of liquid in motor vehicles in a precise manner. Due to the working principle and the pump design, an undesired noise occurs when the armature reaches the mechanical end stops. The noise can be reduced by an adequate self-learning control of the supply energy using a position estimation and velocity control. Based on preliminary investigations /1/, a method for noise reduction is realised by using a user-friendly, tiny and cost-efficient hardware, which enables a use in series manufacturing. The method requires only a voltage and current measurement as input signals. The core of the hardware is an 8-bit microcontroller with 8 kilobytes flash memory including necessary peripherals. A smart software development enables an implementation of the entire noise reduction method onto the tiny flash memory.
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[en] INDUCTION MOTOR VELOCITY CONTROL BY SUBSYNCHRONOUS CASCADE / [pt] CONTROLE DE VELOCIDADE DE MOTORES DE INDUÇÃO USANDO CASCATA SUBSÍNCRONALEIDA ZAMPERLINI 02 May 2007 (has links)
[pt] Discute-se a modelagem de segunda ordem do acionamento
por
motor de indução de rotor bobinado usando cascata
subsíncrona e o controle de velocidade do mesmo. As
estratégias de controle habituais são criticadas e
propõe-se um controlador PI com realimentação
proporcional de
corrente. Propõe-se também um algoritmo de projeto
considerando as possibilidades de ajustes finais. / [en] The second order modeling and speed control of the Wound
Rotor Induction Motor Drive using Subsynchronous Converter
Cascade are discussed. The usual control projects is
criticized, and a PI controller with current proportional
feedback, and also a algorthm for the design with
possibilities of final adjustments are presented.
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[en] INDUCTION MOTOR VELOCITY BY SUBSYNCHRONOUS CASCADE AND 6TH ORDER MODEL / [pt] CONTROLE DE VELOCIDADE DO MOTOR DE INDUÇÃO ATRAVÉS DA CASCATA SUBSÍNCRONA USANDO O MODELO DE 6ª ORDEMGEORGE ALVES SOARES 02 May 2007 (has links)
[pt] O controle de velocidade do motor de indução do rotor
bobinado, através de uma cascata de conversores
estáticos
no rotor, conhecido como Sistema Kramer Estático, é
considerado um dos melhores acionamentos para motores
acima de 500 Hp, devido às suas características de baixo
custo inicial, menor complexidade do sistema de
conversores e regeneração de energia.
Nestas últimas décadas, as pesquisas nesta área se
concentraram basicamente na melhoria da estrutura dos
conversores estáticos, o projeto de controle recebeu
pouca
atenção e sua estrutura de controle continuava inspirada
no controle do motor de corrente contínua. Em um recente
trabalho (1987) foi proposto um controlador PI com
realimantação proporcional de corrente no elo c.c. .
Contudo, este projeto, como os outros, foram baseados em
uma modelagem simples.
Nesta dissertação de mestrado, revê-se e critica-se
modelagens e projetos de controle existentes, desenvolve-
se um modelo de 6ª ordem e propõe-se um projeto de
controle que atente às especificações usuais de
controle.
A estrutura proposta é composta de um regulador de
estado
mais um observador parcial de estado. Esta estrutura é
fisicamente realizável e o seu algoritmo de projeto é
simples, claro e direto. Comprova-se que o uso de
modelos
mais completos e estruturas de controle mais eficazes
não
implicam em controladores complexos e irrealizáveis. / [en] The speed control of wound rotor induction motor by a
static converter cascade (Kramer Static System) is
considered one of the best large motor drive (above 500
Hp.) due to its characteristics of low initial cost, less
complexity of the converters and energy regeneration.
In the last decades, the researches emphasize basicilly
the improvement of the converter structure. The control
design was almost forgotten and its structure was Kept
based on the direct current motor control. In 1987, it was
proposed a PI controller with proportional feedback of
direct current. But, this last design, like the others,
was based on a simple model.
In this dissertation, the modellings and control designs
are reviewed and criticized. Besides this, a sixth order
model is developed and a new control design is proposed in
order to solve the usual control requirements. This
proposed structure is composed of a state regulator plus a
partial state observer. It´s also of easy achievement and
its design algolirhm is simple, easy and direct. It´s
confirmed that the use of morepowerful control structure
doesn´t implacate in complex and unfeasible controller.
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Smart control of electromagnetically driven dosing pumpsKramer, Thomas, Petzold, Martin, Weber, Jürgen, Ohligschläger, Olaf, Müller, Axel January 2016 (has links)
Electromagnetically driven dosing pumps are suitable for metering any kind of liquid in motor vehicles in a precise manner. Due to the working principle and the pump design, an undesired noise occurs when the armature reaches the mechanical end stops. The noise can be reduced by an adequate self-learning control of the supply energy using a position estimation and velocity control. Based on preliminary investigations /1/, a method for noise reduction is realised by using a user-friendly, tiny and cost-efficient hardware, which enables a use in series manufacturing. The method requires only a voltage and current measurement as input signals. The core of the hardware is an 8-bit microcontroller with 8 kilobytes flash memory including necessary peripherals. A smart software development enables an implementation of the entire noise reduction method onto the tiny flash memory.
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Development of a Velocity Controller for Following a Human Using Target Velocity in GPS-Denied EnvironmentsHartman, Chase January 2018 (has links)
No description available.
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Development of a Pseudo-uniform Structural Velocity Metric for Use in Active Structural Acoustic ControlFisher, Jeffery M. 30 August 2010 (has links) (PDF)
Active control of sound and vibration fields has become an strong area of research over the past few decades. In regards to the active control of acoustic radiation from vibration fields, known as active structural acoustic control (ASAC), there have been many different methods employed to understand structural and acoustic relationships and to control vibrations to limit the acoustic radiation. With active sound field control, sensors, usually microphones, need to be dispersed in the sound field, or an array of microphones must be placed directly in the sound field which, in many cases, uses up too much space for practical applications. To remedy this, objective functions have been transferred to the structure, sensing vibrations rather than pressures. A small, integrated array of structural sensors can be placed on the structure, reducing the system's overall footprint. Acoustic energy density has become a well established objective function, which produces a more global effect using only a local measurement. Another benefit of acoustic energy density lies in the breadth of sensor placement. While acoustic energy density has proven successful in active noise control (ANC), the quantity deals with pressures, not surface vibrations. The problem with ASAC is that an objective function with the robustness of acoustic energy density does not yet exist. This thesis focuses on a structural error sensing technique that mimics the properties of acoustic energy density control in the sound field. The presented structural quantity has been termed Vcomp, as it is a composite of multiple terms associated with velocity. Both analytical and experimental results with the control of this quantity are given for a rectangular plate. The control of Vcomp is compared to other objective function including squared velocity, volume velocity and acoustic energy density. In the analytical cases, the benefits include: control at higher structural modes, control largely independent of sensor location, and need for only a single point measurement of squared Vcomp with a compact sensor. The control at higher frequencies can be explained by the control of multiple acoustic radiation modes. Experimental results offer some validity to the analytical benefits but alternate sensing techniques need to be investigates to more fully validate these benefits.
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Splined Speed Control using SpAM (Speed-based Acceleration Maps) for an Autonomous Ground VehicleAnderson, David 15 April 2008 (has links)
There are many forms of speed control for an autonomous ground vehicle currently in development. Most use a simple PID controller to achieve a speed specified by a higher-level motion planning algorithm. Simple controllers may not provide a desired acceleration profile for a ground vehicle. Also, without extensive tuning the PID controller may cause excessive speed overshoot and oscillation.
This paper examines an approach that was designed to allow a greater degree of control while reducing the computing load on the motion planning software.
The SpAM+PI (Speed-based Acceleration Map + Proportional Integral controller) algorithm outlined in this paper uses three inputs: current velocity, desired velocity and desired maximum acceleration, to determine throttle and brake commands that will allow the vehicle to achieve its correct speed. Because this algorithm resides on an external controller it does not add to the computational load of the motion planning computer. Also, with only two inputs that are needed only when there is a change in desired speed or maximum desired acceleration, network traffic between the computers can be greatly reduced.
The algorithm uses splines to smoothly plan a speed profile from the vehicle's current speed to its desired speed. It then uses a lookup table to determine the correct pedal position (throttle or brake) using the current vehicle speed and a desired instantaneous acceleration that was determined in the splining step of the algorithm. Once the pedal position is determined a PI controller is used to minimize error in the system.
The SpAM+PI approach is a novel approach to the speed control of an autonomous vehicle. This academic experiment is tested using Odin, Team Victor Tango's entry into the 2007 DARPA Urban Challenge which won 3rd place and a $500,000 prize. The evaluation of the algorithm exposed both strengths and weaknesses that guide the next step in the development of a speed control algorithm. / Master of Science
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Optimal Velocity and Power Split Control of Hybrid Electric VehiclesUebel, Stephan, Bäker, Bernard 03 March 2017 (has links) (PDF)
An assessment study of a novel approach is presented that combines discrete state-space Dynamic Programming and Pontryagin’s Maximum Principle for online optimal control of hybrid electric vehicles (HEV). In addition to electric energy storage and gear, kinetic energy and travel time are considered states in this paper. After presenting the corresponding model using a parallel HEV as an example, a benchmark method with Dynamic Programming is introduced which is used to show the solution quality of the novel approach. It is illustrated that the proposed method yields a close-to-optimal solution by solving the
optimal control problem over one hundred thousand times faster than the benchmark method. Finally, a potential online usage is assessed by comparing solution quality and calculation time with regard to the quantization of the state space.
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Análise dinâmica de colunas de perfuração de poços de petróleo usando controle linear de velocidade não-colocalizado / Dynamics of oilwell drillstrings using non-colocated linear velocity controlManzatto, Leopoldo Marques 03 May 2011 (has links)
Este trabalho apresenta uma análise paramétrica da reposta dinâmica de colunas de perfuração de poços de petróleo com controle proporcional-integral de velocidade não colocalizado. A operação de perfuração de poços de petróleo e gás em águas profundas consiste na abertura de poços em solo rochoso através de uma broca cuja rotação é controlada por uma mesa rotativa na superfície. O torque imposto pela mesa é transmitido à broca por meio de uma coluna de perfuração. Particularmente no caso de perfuração em águas profundas, as colunas de perfuração podem ser muito extensas e, portanto, bastante flexíveis. As vibrações ocasionadas pela grande flexibilidade das colunas de perfuração são as principais responsáveis por falhas no processo de perfuração. Em particular, o fenômeno não-linear conhecido como stick-slip e relacionado às vibrações torcionais da coluna de perfuração, faz com que um sistema de controle projetado para manter a velocidade da mesa constante dê origem a grandes oscilações na velocidade da broca. Na prática, este fenômeno é amplificado pela inerente não-linearidade do contato entre broca e formação rochosa e pela forte não colocalização entre mesa rotativa e broca. Este trabalho tem por principal objetivo realizar uma análise paramétrica da dinâmica do processo de perfuração, usando um modelo de dois graus de liberdade para representar o conjunto mesa rotativa, coluna de perfuração e broca, para identificar condições nas quais uma lei de controle simples do tipo linear proporcional-integral pode fornecer um desempenho de perfuração estável e satisfatório. / This paper presents a parametric analysis of the dynamics of oilwell drillstrings with non-collocated proportional-integral velocity control. The drilling operation for oil and gas in deep waters consists of opening wells in rocky ground formation by a drill, whose angular speed is controlled by a rotary table at the surface. The torque applied by the table is transmitted to the drill-bit through the drillstring. Particularly in the deepwater drilling case, the drillstring can be very long and therefore very flexible. The vibrations caused by the great flexibility of drilling columns are mainly responsible for the failures in the drilling process. In particular, the nonlinear phenomenon known as stick-slip and related to the torsional vibration of the drillstring, makes that a control system designed to maintain a constant angular velocity at the table yield large variations at the drill-bit angular velocity. In practice, this phenomenon is amplified by the inherent nonlinearity of the contact between drill bit and rock formation and by the strong non-colocalization between rotary table and drill-bit. The main objective of this work is to perform a parametric analysis of the dynamics of the drilling process, using a two degrees of freedom model in order to represent the rotary table assembly, the drilling column and drill-bit, to identify conditions in which a simple control law, such as a linear proportional-integral velocity control, can provide a stable and satisfactory drilling performance.
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