Tuning of a Lag-Lead Compensator Used with a First Order Plus an Integrator Process (original) (raw)
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viXra, 2016
Lag-lead compensators are well known in automatic control engineering. They have 4 parameters to be adjusted (tuned) for proper operation. The frequency response of the control system or the root locus plot are traditionally used to tune the compensator in a lengthy procedure. A highly oscillating second-order process has a time response to a unit step input of 85.4 % maximum overshoot and about 6 seconds settling time is controlled using a lag-lead compensator (through simulation). The lag-lead compensator is tuned by minimizing the sum of time multiplied by the absolute error (ITAE) of the control system using MATLAB. Three functional constrains are used to control the performance of the lag-lead compensated control system. The result was reducing the process oscillation to 6.926 % overshoot and a 1.413 seconds settling time. The steady-state characteristics of closed-loop control system using the lag-lead compensator were excellent. It is possible reduce the steady-state error to...
Tuning of a Feedback Lag-Lead First-Order Compensator Used with a Delayed Double Integrating Process
2015
The problem of controlling an unstable delayed double integrating process using a feedforward first-order lag-lead compensator is studied. The effect of time delay of the process in a range between 1 and 12 seconds is considered. The compensator is tuned using MATLAB optimization toolbox with five forms of the objective function in terms of the error between the step time response of the closed-loop control system and the response steady-state value. Using the proposed compensator with the delayed double integrating process indicates the robustness of the compensator in the time delay range used with superior time-based specifications compared with other techniques based on using PID controllers with the same process.
International journal of advances in engineering and technology, 2015
Robustness is one of the requirements used in controllers and compensators design. The designs presented in the previous papers did not consider the robustness of the controller or compensator. Therefore, the objective of this paper is to investigate the robustness of feedback first-order lag-lead, feedforward second-order lag-lead and feedforward first-order lag-lead compensators used to control second-order processes against uncertainty in the process parameters. A variation of ± 20 % in process parameters is considered through simulation to study its effect on the system performance parameters using the tuned controllers. With a feedback first-order lag-lead compensator controlling a highly oscillating second order process, the variation in process natural frequency and damping ratio has small effect on the maximum percentage overshoot, settling time and the phase margin of the control system. The phase margin is above 74 degrees for all the changes in the process parameters providing robust compensator characteristics. The phase margin of the control system using the proposed compensators for the range of the variation of the process parameters is above 56 degrees, the maximum percentage overshoot for a step input is less than 11.5 % and the settling time does not exceed 1.41 seconds indicating the robustness of the three compensators.
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2011 9th IEEE International Conference on Control and Automation (ICCA), 2011
In this paper three different methods for the synthesis of lead-lag compensators that meet design specifications on the phase margin and the gain crossover frequency are presented. These numerical and graphical methods are based on the choice of a degree of freedom of the regulators. These procedures aim to satisfy an additional specification for robust control: the gain margin, the complementary modulus margin or a specification on the settling time of the controlled system.
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A Review note on Compensator Design for Control Education and Engineering
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The compensators are one of the most important aspects in any undergraduate control engineering courses owing to their widespread industrial applications. The degree of convergence of the output waveform for any compensator depends upon proper selection and tuning of the compensator. In this paper the compensator parameters (α, β, τ) of the lead, lag and lag-lead compensators are tuned to their optimum values using the conventional root locus as well as frequency response approach. The compensator algorithm is studied using MATLAB and usefulness of these compensators for controlling process variables are demonstrated using proper tuning. The comparative studies showing promising results are discussed with suitable examples.
The problem of controlling an unstable delayed double integrating process using a feedback first-order lag-lead compensator is studied. The effect of time delay of the process in a range between 0.1 and 0.8 seconds is considered. The compensator is tuned using MATLAB optimization toolbox with five forms of the objective function in terms of the error between the step time response of the closed-loop control system and the response steady-state value. Using the proposed compensator with the delayed double integrating process indicates the robustness of the compensator in the time delay range used with superior time-based specifications. The dynamics of the control system are compared with other technique based on using a feedforward first-order lag-lead compensator.
2015
The problem of controlling an unstable delayed double integrating process with fractional delay using a feed forward first-order lag-lead compensator is studied. The effect of time delay of the process in a range between 0.1 and 0.9 seconds is considered. The compensator is tuned using MATLAB optimization toolbox with five forms of the objective function in terms of the error between the step time response of the closed-loop control system and the response steady-state value. Using the proposed compensator with the fractional delayed double integrating process indicates the robustness of the compensator in the time delay range used with superior time-based specifications compared with other technique based on PID controller .
Auto-tuning of phase lead/lag compensators
Automatica, 2004
In the tuning of phase lead/lag compensators, knowledge of speciÿc points on the frequency response of the plant are required. Such points are speciÿed by their frequency, gain and phase and are not readily available without an accurate model of the plant. Yet such information is important for any auto-tuning procedure to succeed. In this paper, relays with hysterisis are tuned to determine points on the frequency response of a plant with a user-speciÿed gain, g0 or phase, 0. On-line algorithms are developed to tune the operating point of the relay feedback system so that the resulting oscillations correspond to the frequency response of the plant with either gain, g0 or phase, 0. Tuning involves setting either the amplitude of the relay or its hysterisis width. Improvement over the simple application of the describing function is also shown. The results are applied to the auto-tuning of phase lead and lag compensators. Simulations are presented to illustrate the auto-tuning procedures.
Optimum Speed Control of DC Motor applying Lag Lead Compensator
International Journal of Engineering, 2020
Differential equations describing motor’s dynamic performance are considered in the development of transfer function equations and their Laplace transforms obtained for additional investigation. For the sake of reliability, typical data for two DC Motor modelsare incorporated within Matlab/Simulink program to demonstrate the elementary time domain performance of the system. A lead lag compensator applied as control method to control the speed of DC Motor. The nonlinear programming optimization algorithm “fmincon; computes a constrained minimum of an objective function of a number of variables starting at a preliminary estimate” used in the optimization routine to reach finest locations for the added pole and zero to attain the optimal parameters for the designed lead lag compensator. A standard test step signal used as a desired input speed to study the effectiveness of the proposed controller based on the performance of the system. In order to validate the controller tracking for s...