Unity Feedback Control System Research Articles

Performance comparison between variants PID controllers and unity feedback control system for the response of the angular position of the DC motor

This paper proposed a detailed study for the response of angular position of the rotor of a DC motor. It is a comparative analysis to the behavior of the DC motor when the motor is alone and when it is with controllers. Furthermore, a comparison between the responses of controllers themselves. A conventional PID controller which was tuned by using Ziegler and Nichols method was proposed in this paper. Also, Modification PID controllers were proposed in this paper. The modification PID controllers are PI-D controller and I-PD controller. Mathematical calculations were done to get the transfer functions for the DC motor and the controllers. Time domain specifications and figures were obtained for each case by using Matlab program. The obtained results were summarized in tables. This paper determined which the controller is the best one depending on the obtained figures and the time domain specifications.

Verifying and Simulating of the Novel Analytical Method of the Steady-State Error for Nonunity Feedback Control Systems

Traditionally, the first step to analyze the steady-state error of nonunity feedback control system is to convert the system into an equivalent unity feedback control system, and calculate the steady-state error by using the concept of type number for unity feedback control system. In 2011, Mou is based on the concept of old type number and the definition of new steady-state error functione(t)=(1/KH)r(t)-y(t) by Kuo to offer the method for calculating the steady-state error of nonunity feedback control system. In this paper, three typical examples will be analyzed by the calculation of step response and by the simulation of Matlab. Therefore, we can prove that the definition of new steady-state error function e(t)=(1/KH)r(t)-y(t) by Kuo and the concept of old type number are useful to solve the steady-state error of nonunity feedback control system.

AUTOMATIC GAIN CONTROL FOR UNITY FEEDBACK CONTROL SYSTEMS

In this paper, an automatic gain control scheme is proposed for analyses and designs of unity feedback control systems. It is consisted of a fast command tracking loop and a slow gain adaptive loop. The overall system is equivalent to a conventional automatic gain control loop with command tracking error input. It gives good command tracking behaviour while keeping robust characteristic of the original automatic gain control loop. It gives good robustness for coping with fast large parameter and load disturbance variations also. The stability of the controlled systems and effective of the proposed method are verified by root-loci, time responses, frequency responses, large parameter variations and fast large load disturbances testing with two numerical examples.

Design of Unity Feedback Control Systems Based on the Method of Inequalities.

In this paper, we develop a computer-aided control system design based on the method of inequalities proposed by Zakian. First, for single-input single-output unity feedback systems, we give a simple pole-zero placement algorithm that can prevent specified pole-zero cancellation. Then this algorithm is used to develop a computer-aided design (CAD) system based on the method of inequalities. As a parameter search algorithm, we use Rosenbrock's moving boundary method. For efficient parameter search, we propose a simple modification of the algorithm, which takes account of the role of the tuning parameters. Since the developed CAD system is written as m-tiles of MATLAB, it can be widely used on various computers, from personal computers to workstations. A design example is presented to illustrate the effectiveness of the proposed CAD system.

'EDCON': an educational control system analysis and design program

A PC-based software package called EDCON which is a useful tool for teaching basic control system theory is discussed. It provides a user friendly environment that allows students to vary system parameters and design requirements to see the effects on system response. The package is designed around the root locus plot of a unity feedback control system. It uses a second order approximation technique to calculate and graph the unit step response of the system for any value of gain, and gives all the time and frequency parameters of the system. The package was developed to be used as a complement to an undergraduate course in control systems analysis and design. >

A Computer Simulation For Control SystemsDesign

A menu-driven graphics-based simulation package called DESIGN has been developed. It enables the users to add/delete poles or zeros and vary design requirements such as the value of the gain, damping factor, overshoot, delay time, rise time, bandwidth, resonance frequency, etc., to see the effects on system response. The package is designed around the root locus plot of a unity feedback control system in a window environment. It is a useful tool for both the teachers and the students in a basic control system theory course with a special emphasis on design.

Graphical analysis of a class of non-linear feedback control systems with step input†

The class of systems considered in this investigation is a cascade combination of a linear memory system and a non-linear no-memory system in the forward path of a unity feedback control system. The output of the non-linear no-memory system is assumed to be a polynomial function of the input. Regardless of the exact nature of the non-linearity, the objective of this method of analysis is to predict the behaviour of higher-order non-linear systems with different initial conditions for step inputs. Two different cascade combinations of linear and non-linear blocks in the forward path are considered. For both configurations a similar non-linear differential equation is obtained for some variable in the system. The non-linear differential equation is further reduced to a first-order equation, explicitly independent of the independent variable, time t. Treating all other coefficients as parameters and eliminating each in turn, finally the required phase-plane trajectory is obtained.

On the suppression of limit-cycle oscillations

A procedure is presented for the suppression of limit-cycle oscillations in unity-feedback control systems which have an on-off type nonlinearity in cascade with a linear transfer function. The procedure is based on the introduction of a minor loop into the system. This produces a high-frequency periodic signal at the input of the nonlinearity, and thereby limit-cycle oscillations are suppressed.