8 research outputs found
Perancangan Dan Implementasi Kontroler Sliding Mode Pada Pengaturan Kecepatan Motor Induksi Tiga Fasa
Penggunaan motor induksi pada dunia industri banyak kita temui. Hal ini dikarenakan perawatannya yang relatif murah, akan tetapi pengaturan kecepatannya susah. Oleh karena itu, dibutuhkan suatu kontroler untuk mengatur kinerja dari suatu motor induksi itu sendiri. Penggunaan PLC (Programmable Logic Controller) sebagai kontroler telah dipercaya sebagai pengendali utama di dalam dunia industri karena telah terbukti kehandalan dan fleksibilitasnya. Banyak metode pengaturan kecepatan telah digunakan mulai dari pengontrolan menggunakan kontroler PID sampai dengan penggunaan kontroler Sliding Mode Control (SMC). SMC merupakan kendali umpan Balik pensaklaran frekuensi tinggi yang memiliki sifat kokoh. Kendali SMC dipilih karena kekokohan yang dimiliki sistem kendali ini diharapkan dapat mengatasi permasalahan Perubahan parameter dari motor induksi akibat pembebanan. Perubahan parameter dapat mengakibatkan Perubahan respon yang cukup signifikan. Namun kekurangan yang dimiliki oleh kendali SMC adalah timbulnya fenomena chattering yang berpengaruh terhadap stabilitas sistem kendali. Dari hasil penelitiann dapat dilihat bahwa SMC memiliki respon keluaran yang baik dalam meredam chattering. Sifat kokoh dari kontroler SMC dimana dapat mengembalikan lintasan trayektori ke permukaan luncur dengan cepat sampai 0,2 detik
Perancangan dan Implementasi Kontroler Sliding Mode Pada Pengaturan Kecepatan Motor Induksi Tiga Fasa
Penggunaan motor induksi pada dunia industri banyak kita temui. Hal ini dikarenakan perawatannya yang relatif murah, akan tetapi pengaturan kecepatannya susah. Oleh karena itu, dibutuhkan suatu kontroler untuk mengatur kinerja dari suatu motor induksi itu sendiri. Penggunaan PLC (Programmable Logic Controller) sebagai kontroler telah dipercaya sebagai pengendali utama di dalam dunia industri karena telah terbukti kehandalan dan fleksibilitasnya. Banyak metode pengaturan kecepatan telah digunakan mulai dari pengontrolan menggunakan kontroler PID sampai dengan penggunaan kontroler Sliding Mode Control (SMC). SMC merupakan kendali umpan balik pensaklaran frekuensi tinggi yang memiliki sifat kokoh. Kendali SMC dipilih karena kekokohan yang dimiliki sistem kendali ini diharapkan dapat mengatasi permasalahan perubahan parameter dari motor induksi akibat pembebanan. Perubahan parameter dapat mengakibatkan perubahan respon yang cukup signifikan. Namun kekurangan yang dimiliki oleh kendali SMC adalah timbulnya fenomena chattering yang berpengaruh terhadap stabilitas sistem kendali. Dari hasil penelitiann dapat dilihat bahwa SMC memiliki respon keluaran yang baik dalam meredam chattering. Sifat kokoh dari kontroler SMC dimana dapat mengembalikan lintasan trayektori ke permukaan luncur dengan cepat sampai 0,2 detik
Disturbance Observer-based Robust Control and Its Applications: 35th Anniversary Overview
Disturbance Observer has been one of the most widely used robust control
tools since it was proposed in 1983. This paper introduces the origins of
Disturbance Observer and presents a survey of the major results on Disturbance
Observer-based robust control in the last thirty-five years. Furthermore, it
explains the analysis and synthesis techniques of Disturbance Observer-based
robust control for linear and nonlinear systems by using a unified framework.
In the last section, this paper presents concluding remarks on Disturbance
Observer-based robust control and its engineering applications.Comment: 12 pages, 4 figure
Novel Strategies to design Controllers and State Predictors based on Disturbance Observers
[ES] Los sistemas de ingenierÃa o fÃsicos suelen ser inciertos. Su incertidumbre se manifiesta cuando el sistema muestra comportamientos que son relativamente diferentes a los que su modelo predice; estando principalmente causada por: errores de modelado; dinámicas desconocidas; cambios en las propiedades del sistema; interacciones aleatorias con otros sistemas; o cambios en las condiciones de operación.
Durante los últimos 40 años, se ha demostrado reiteradamente que las incertidumbres de los sistemas pueden tener efectos muy negativos sobre el comportamiento de un controlador si éstas no se consideran adecuadamente sus formulaciones matemáticas. Por esta razón, una parte importante de la investigación actual está centrada en este tema; buscando las formas mas adecuadas para representar matemáticamente las incertidumbres de los sistemas, asà como buscando nuevas herramientas matemáticas que permitan hacer uso de ésta representación de la incertidumbre con el objetivo de diseñar algoritmos de control robustos.
En esta tesis se presentan nuevas aportaciones en esta lÃnea. Concretamente, se desarrollan nuevas metodologÃas para diseñar controladores (DOBCs) y predictores (DOBPs) para sistemas dinámicos inciertos basados en observadores de perturbaciones. La principal aportación es demostrar que los DOBCs se pueden sintetizar desde un enfoque de control óptimo; siendo su principal criterio de diseño el de aproximar la -irrealizable- señal de control óptima que minimiza un Ãndice de coste cuadrático sujeto a un modelo dinámico lineal (LTI). Este nuevo enfoque de diseño es indistintamente válido para modelos SISO/MIMO con múltiples o únicas perturbaciones. Además permite un ajuste del controlador muy intuitivo gracias a las matrices de ponderación del coste. De forma similar; los DOBPs se construyen con el objetivo de aproximar la solución temporal un sistema dinámico perturbado.
Con el objetivo de contextualizar la aportación, el documento también incluye un breve resumen de los principales métodos de control robusto y el impacto que han tenido en la revolución tecnológica del siglo XXI; algunas discusiones sobre la utilidad de los modelos LTI perturbados para representar sistemas dinámicos inciertos; y algunas relaciones, comparaciones y simulaciones numéricas de los métodos propuestos con otras técnicas de control.[CA] Els sistemes d'enginyeria o fÃsics solen ser incerts. La seua incertesa es manifesta quan el sistema mostra comportaments que són relativament diferents als que el seu model prediu; sent principalment causada per: errors de modelatge; dinà miques desconegudes; canvis en les propietats del sistema; interaccions aleatòries amb altres sistemes; o canvis en les condicions d'operació.
Durant els últims 40 anys, s'ha demostrat reiteradament que les incerteses dels sistemes poden tindre efectes molt negatius sobre el comportament d'un controlador si aquestes no es consideren adequadament les seues formulacions matemà tiques. Per aquesta raó, una part important de la investigació actual està centrada en aquest tema; buscant les formes mes adequades per a representar matemà ticament les incerteses dels sistemes, aixà com buscant noves tècniques matemà tiques que permeten fer ús d'aquesta representació de la incertesa amb l'objectiu de dissenyar algorismes de control robustos.
En aquesta tesi es presenten noves aportacions en aquesta lÃnia. Concretament, es desenvolupen noves metodologies per a dissenyar controladors (DOBCs) i predictors (DOBPs) per a sistemes dinà mics incerts basats en observadors de pertorbacions. La principal aportació és demostrar que els DOBCs es poden sintetitzar des d'un punt de vista de control òptim; sent el seu principal criteri de disseny el d'aproximar la -irrealitzable- senyal de control òptima que minimitza un Ãndex de cost quadrà tic restringit a un model dinà mic lineal (LTI). Aquest nou plantejament és indistintament và lid per a models SISO/MIMO amb múltiples o úniques pertorbacions. A més permet un ajust del controlador molt intuïtiu grà cies a les matrius de ponderació del cost. De manera similar; els DOBPs es construeixen amb l'objectiu d'aproximar la solució temporal un sistema dinà mic pertorbat.
Amb l'objectiu de contextualitzar l'aportació, el document també inclou un breu resum dels principals mètodes de control robust i l'impacte que han tingut en la revolució tecnològica del segle XXI; algunes discussions sobre la utilitat dels models LTI pertorbats per a representar sistemes dinà mics incerts; i algunes relacions, comparacions i simulacions numèriques dels mètodes proposats amb altres tècniques de control.[EN] Engineering or physical systems are used to be uncertain. Its uncertainty is manifested whenever the system shows behaviors that are relatively different than the ones predicted by its model; being mostly caused by: modeling errors; unknown dynamics; changes in the system properties; random interactions with other systems; or changes in the operating conditions.
Through the last 40 years, it has been persistently proved that the system uncertainties could have very negative effects in the performance of a feedback regulator if they are not properly considered in the mathematical formulations of the employed algorithms. Thus, an important part of the recent research is focused on this topic; searching for the most appropriate ways to mathematically represent the system uncertainties and looking for new mathematical-tools that permit to make use of such uncertainty-representation in order to design robust control algorithms.
In this thesis, new contributions in this line are provided. Concretely, novel methodologies to design Disturbance Observer-Based Controllers (DOBCs) and Predictors (DOBPs) for uncertain dynamic systems are developed. The main contribution is to show that the DOBCs can be constructed from an optimality-based approach, with the main objective of approximating the -unrealizable- optimal control signal that minimizes a quadratic-cost performance index subject to a LTI disturbed model constraint. This novel robust control design is indistinctly valid for SISO/MIMO models with single/multiple matched/mismatched disturbances; offering also a highly intuitive and versatile tuning through the weighting matrices. Similarly, the DOBPs are synthesized in order to approximate the time-domain solution of LTI disturbed models.
For the sake of completeness, the document also includes a brief review of the main robust control methods and the impact that they have had on the technological revolution of the 21st century; some discussions about the usefulness of the LTI disturbed models for representing uncertain dynamic systems; and different relationships, comparisons and numerical simulations, of the proposed methods with other control approaches.Castillo Frasquet, A. (2021). Novel Strategies to design Controllers and State Predictors based on Disturbance Observers [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/165034TESI
Robust vehicle steering control design based on the disturbance observer
A robust steering controller is introduced for improving the yaw dynamics of a passenger car. A specific two degree of freedom control architecture known as the disturbance observer is adapted to the vehicle yaw dynamics control problem and shown to robustly improve performance. The relevant design specifications are formulated in terms of eigenvalues (T-stability) and in frequency domain as bounds on weighted sensitivity and complementary sensitivity functions (B-stability). The parameter space method is used to map the specifications for controller design. A Popov criterion based nonlinear stability analysis is also carried out to prove absolute stability in the presence of actuator rate limitation. Simulations are used to demonstrate the effectiveness of the final design
Robust Vehicle Steering Control Design Based on the Disturbance Observer
A robust steering controller is introduced for improving the yaw dynamics of a passenger car. A specific two degree of freedom control architecture known as the disturbance observer is adapted to the vehicle yaw dynamics control problem and shown to robustly improve performance. The relevant design specifications are formulated in terms of eigenvalues (Gamma-stability) and in frequency domain as bounds on weighted sensitivity and complementary sensitivity functions (B-stability). The parameter space method is used to map the specifications for controller design. A Popov criterion based nonlinear stability analysis is also carried out to prove robust absolute stability (Theta-stability) in the presence of actuator rate limitation. Simulations are used to demonstrate the effectiveness of the final design
DESIGN OF A SEMI-ACTIVE STEERING SYSTEM FOR A PASSENGER CAR
This thesis presents research into an improved active steering system technology for a
passenger car road vehicle, based on the concept of steer-by-wire (SBW) but possessing
additional safety features and advanced control algorithms to enable active steering
intervention. An innovative active steering system has been developed as 'Semi-Active
Steering' (SAS) in which the rigid steering shaft is replaced with a low stiffness resilient
shaft (LSRS). This allows active steer to be performed by producing more or less steer angle
to the front steered road wheels relative to the steering wheel input angle. The system could
switch to either being 'active' or 'conventional' depending on the running conditions of the
vehicle; e.g. during normal driving conditions, the steering system behaves similarly to a
power-assisted steering system, but under extreme conditions the control system may
intervene in the vehicle driving control. The driver control input at the steering wheel is
transmitted to the steered wheels via a controlled steering motor and in the event of motor
failure, the LSRS provides a basic steering function. During operation of the SAS, a reaction
motor applies counter torque to the steering wheel which simulates the steering 'feel'
experienced in a conventional steering system and also applies equal and opposite counter
torque to eliminate disturbance force from being felt at the steering wheel during active
control operation.
The thesis starts with the development of a mathematical model for a cornering road
vehicle fitted with hydraulic power-assisted steering, in order to understand the relationships
between steering characteristics such as steering feel, steering wheel torque and power boost
characteristic. The mathematical model is then used to predict the behaviour of a vehicle
fitted with the LSRS to represent the SAS system in the event of system failure. The
theoretical minimum range of stiffness values of the flexible shaft to maintain safe driving
was predicted.
Experiments on a real vehicle fitted with an LSRS steering shaft simulator have been
conducted in order to validate the mathematical model. It was found that a vehicle fitted with
a suitable range of steering shaft stiffness was stable and safe to be driven. The mathematical
model was also used to predict vehicle characteristics under different driving conditions
which were impossible to conduct safely as experiments.
Novel control algorithms for the SAS system were developed to include two main criteria,
viz. power-assistance and active steer. An ideal power boost characteristic curve for a
hydraulic power-assisted steering was selected and modified and a control strategy similar to
Steer-by-Wire (SBW) was implemented on the SAS system.
A full-vehicle computer model of a selected passenger car was generated using
ADAMS/car software in order to demonstrate the implementation of the proposed SAS
system. The power-assistance characteristics were optimized and parameters were determined
by using an iteration technique inside the ADAMS/car software. An example of an open-loop
control system was selected to demonstrate how the vehicle could display either under-steer
or over-steer depending on the vehicle motion.
The simulation results showed that a vehicle fitted with the SAS system could have a
much better performance in terms of safety and vehicle control as compared to a conventional
vehicle. The characteristics of the SAS system met all the requirements of a robust steering
system. It is concluded that the SAS has advantages which could lead to its being safely fitted
to passenger cars in the future.
Keywords: steer-by-wire, active steering, innovative, power-assisted steering, steering
control, flexible shaft, steering intervention, system failure, safety features