Explore the vast range of titles available.

We present an output tracking problem for a non-minimum phase nonlinear system. In this paper, the input control design to solve the output tracking problem is to use the input output linearization method. The use of the input output linearization method cannot be initiated from output causing the system to be non-minimum phase. Therefore the output of the system will be redefined such that the system will become minimum phase with respect to a new output.

The purpose of this article is to introduce an app to draw the asymptotes of Bode diagram module and phase from each constituent elementary factors of any transfer function for minimum and non‐minimal phase systems without transport delay. The Bode diagram is the most used tool in the frequency response method. Python and several Python modules were used to program the app to perform the operations as well as the Qt5 design was used to create a simple graphical user interface for the app and all this in the Linux operating system and the app's source code can also be run in Windows operating system with no adjustments or modifications. The app purpose is to assist students in learning the frequency response concepts and drawing of Bode diagram using asymptotes of magnitude and phase. For students the non‐minimum phase system Bode diagram is more difficult to draw than a minimum phase system due to the presence of zeros and/or poles on right half side of s $$ s $$ ‐plane. This application should be used by students as a help and not simply to solve problems and for teachers the application can be used to improve their classes by showing the step by step of drawing the Bode diagram with the figures obtained by the application. The app's executable file is available on release link in https://github.com/Magno‐Meza‐UFABC/Magno‐Meza‐UFABC/releases/tag/v.1.0 Python was used to draw the asymptotes of a non‐minimal and minimal phase transfer function in the Bode diagram. The sum of the asymptotes is performed by part to assist the interested in learning and understanding the Bode diagram.

This paper proposes a method to stabilize and enhance the dynamic performance of a cascaded DC-DC system by adaptively reshaping the source output impedance. The method aims to reduce the ratio of the source output impedance to the load input impedance, referred to as the minor loop gain, to eliminate the interaction between the load and the source systems. This interaction can deteriorate the dynamic performance or might lead to instability. Thus, the bus current is used to improve the dynamic performance by reducing the magnitude of the source’s output impedance adaptively according to the loading condition such that the dynamic performance is consistently improved. Utilizing the bus current facilitates the compatibility between the proposed controller and most widely used DC-DC converters controlled in voltage mode, including non-minimum phase converters. In addition to the flexibility the bus current provides to embed the proposed solution with conventional control schemes. Experimental results have validated the effectiveness of the proposed controller along with time-based simulation and theoretical analysis, for minimum and non-minimum phase converters.

Design of centralised disturbance rejection controllers for an highly interacting MIMO quadruple tank process is tedious. Recently, centralised disturbance rejection Fractional Order LQI (FOLQI) controller is designed for such system to meet the desired specifications with better performance than various disturbance rejection controllers that are available in the literature. In this paper, an optimisation problem is formulated to obtain the optimal parameters of FOLQI controller providing minimum control effort by applying various widely used heuristic methods like Cuckoo Search (CS), Accelerated Particle Swarm Optimisation (APSO) and FireFly (FF) algorithms. A detailed simulation study is carried out to compare the performance of the FOLQI and Integer Order LQI (IOLQI) controllers obtained by these heuristic algorithms under disturbance and parameter uncertainty conditions. From the simulation study it is inferred that (i) FOLQI controller provides better time domain specifications % Mp, ts and J in comparison to IOLQI controllers and (ii) FF tuned FOLQI and IOLQI controllers provide better robustness characteristics compared to CS and APSO tuned controllers.

The stabilizability problem of an unstable non‐minimum phase (NMP) plant, controlled over a signal‐to‐noise ratio (SNR) constrained channel with transmission delay, is investigated in this article. A dynamical output feedback controller is used to stabilize the single‐input single‐output plant where the control data are exchanged via an NMP bandwidth‐limited communication medium. For the first time, a novel description of SNR is used to solve stabilizability problem when the NMP channel imposes a constant delay on transmitted data. It is demonstrated that the presence of time‐delay in the channel model as well as its NMP zeros increases the value of SNR needed for stabilizability of the closed‐loop system. The main results are illustrated and discussed through numerical examples. © 2016 Wiley Periodicals, Inc. Complexity 21: 557–565, 2016

Microgrids integrate various distributed energy resources to enhance energy reliability and sustainability. Power electronic converters are vital in microgrids since they provide efficient, reliable, and flexible operation. There are numerous controllers available that can be applied to these converters, and lately, fractional-order controllers (FOC) have gathered huge recognition. These controllers provide enhanced flexibility and superior performance in managing dynamic behavior. There are various structures of FOCs, and this article predominantly focuses on comparing different cascaded fractional order controllers (C-FOC). Four distinct topologies of cascaded fractional order proportional integral (C-FOPI) controllers are selected for comparison with one another and with the cascaded proportional integral controller used in a non-minimum phase converter, such as the boost converter employed in a microgrid system. The controllers are optimized using the Elephant Herd Optimization (EHO) algorithm with the Integral of Time-weighted Absolute Error (ITAE) serving as the performance metric. Each controller is subject to variation in system changes, and the outcomes are documented and correlated to ascertain the optimum structure. The simulation outcomes endorsed notable advancements in terms of transient and steady-state performance, featuring improved resilience to parameter changes, a reduction of 36.6% in settling time, 15% in overshoot, 20.1% in rise time, an improved phase margin of more than 51% and more than 50% reduction in performance indices compared to traditional cascaded proportional integral controllers (PI-PI).

DC-DC converters are critical components in contemporary power electronics systems, facilitating efficient power conversion and distribution across various applications. Conventional step-up converters typically exhibit a right-half-plane zero in their transfer function, leading to non-minimum phase characteristics. This behavior restricts the stability margin and makes the dynamic response time undesirable. This paper presents a novel topology designed to address the non-minimum phase problem. In this converter, a portion of the energy from the input source is transferred to the output via the coupled inductor. Additionally, the required voltage gain can be attained by utilizing the quantity and positioning of the coupled inductor’s secondary windings. The voltage gain, stress voltage on semiconductor devices, and losses are calculated through steady-state analysis. The control signal to the output voltage transfer function is obtained through small signal analysis. The results from the laboratory prototype and simulations in two distinct scenarios are presented to validate the performance and integrity of the mathematical analysis.

We consider tracking control for multibody systems which are modeled using holonomic and non-holonomic constraints. Furthermore, the systems may be underactuated and contain kinematic loops and are thus described by a set of differential-algebraic equations that cannot be reformulated as ordinary differential equations in general. We propose a control strategy which combines a feedforward controller based on the servo-constraints approach with a feedback controller based on a recent funnel control design. As an important tool for both approaches, we present a new procedure to derive the internal dynamics of a multibody system. Furthermore, we present a feasible set of coordinates for the internal dynamics avoiding the effort involved with the computation of the Byrnes–Isidori form. The control design is demonstrated by a simulation for a nonlinear non-minimum phase multi-input, multi-output robotic manipulator with kinematic loop.

With the capability of high speed flying, a more reliable and cost efficient way to access space is provided by hypersonic flight vehicles. Controller design, as key technology to make hypersonic flight feasible and efficient, has numerous challenges stemming from large flight envelope with extreme range of operation conditions, strong interactions between elastic airframe, the propulsion system and the structural dynamics. This paper briefly presents several commonly studied hypersonic flight dynamics such as winged-cone model, truth model, curve-fitted model, control oriented model and re-entry motion. In view of different schemes such as linearizing at the trim state, input-output linearization, characteristic modeling, and back-stepping, the recent research on hypersonic flight control is reviewed and the comparison is presented. To show the challenges for hypersonic flight control, some specific characteristics of hypersonic flight are discussed and the potential future research is addressed with dealing with actuator dynamics, aerodynamic/reaction-jet control, flexible effects, non-minimum phase problem and dynamics interaction.

Hydropower unit plays a more and more important role in guaranteeing the safe and stable operation of the power system and providing high-quality power supply. As a non-minimum phase system, one of the most concerned problems is the design of hydro-turbine governing system (HTGS). Internal mode control (IMC) is a good method for turbine speed control system. To solve the problem of inverse difficulty when conventional IMC is used for hydro-generator (non-minimum phase system), this paper proposes an improved IMC based on generalized inverse solver (GIS). The article verifies the superiority of this control method for different types of linear systems through simulation. At the same time, this method is applied to the hydro generator speed control system. Compared with IMC and some improved PID algorithms, IMC with GIS algorithm shows advantages in terms of tracking response and anti-disturbance performance. It achieves overshoot-free tracking with 30% less inversion and 31% shorter recovery time after failure. The response time fluctuation is reduced by 46% compared with other algorithms, which shows stronger robustness when facing the parameter ingestion problem.