Internal Model Control PID Research Articles

A Multitransmission Event-Based Architecture for Energy-Efficient Autotuning Wireless Controls

We propose a periodic event-based control scheme in which, when the sensor triggers an event, also past and subsequent values of the controlled variable are transmitted. We employ this idea to obtain a stability condition independent of the used event-triggering mechanism. In turn, we exploit this independence to devise a methodology for extending existing controller (auto)tuning rules to the event-based setting and provide an example with the internal model control PID (IMC-PID) rule. We then abstract the functionalities that a wireless sensor node has to offer for implementing our scheme and finally present such a node, physically realized in a completely hardware-based form to the advantage of both energy efficiency and security. Simulations results and experiments with the so-obtained control architecture (wireless sensor node plus event-based IMC-PID) are reported.

Extended State Observer-Based IMC-PID Tracking Control of PMLSM Servo Systems

Servo systems driven by a permanent magnet linear synchronous motor (PMLSM) are often affected by uncertain disturbances, such as magnetic resistance, friction, and external disturbances, which increase tracking errors and reduce motion accuracy. Traditional control methods may have difficulty to achieve satisfactory control performance in terms of tracking accuracy and disturbance rejection. In this paper, we propose an internal model control PID method based on a model linear extended state observer, which is termed as IMC-PID-MLESO method. With this method, the nominal model parameters of the PMLSM servo system are obtained via system identification. The model linear extended state observer (MLESO), with known parameter information, is designed to improve the estimation accuracy for the system states and total unknown uncertainties. As the uncertainties are compensated in the feedback control law, the PMLSM servo system model is transformed into a known nominal model. Based on the nominal model, the IMC-PID feedback controller is designed to ensure satisfactory performance on disturbance rejection and tracking error reduction. Simulation and experimental results show that the IMC-PID-MLESO method can effectively improve the position tracking accuracy of the PMLSM servo system and rapidly suppress the system disturbance.

Shaft Speed Control of the Gas Turbine Based on Active Disturbance Rejection Control

As a clean energy engine, the gas turbine has many challenges in its shaft speed control such as strong nonlinearity and various external disturbances. However, conventional controllers such as proportional-integral-derivative (PID) controllers are not able to obtain satisfactory performance in disturbance rejection when the operating point is changing. To handle with the strong nonlinearity and reject possible disturbances more effectively, the linear active disturbance rejection controller (LADRC) is applied to the shaft speed control system of the gas turbine based on an experimental tuning procedure. Moreover, Skogestad Internal Model Control-PID (SIMC-PID) and fractional order PID (FOPID) are chosen as comparative controllers. Eventually, Monte Carlo trials are carried out and maximum sensitivities are calculated in order to test the robustness of controllers. Simulation results illustrate the advantages of LADRC in both reference tracking and rejections of different disturbances.

Microtension control for a yarn winding system with an IMC PID controller

In this paper, feedforward compensation and an internal model control (IMC) PID tuning method to maintain the yarn tension within a micro-boundary range are proposed. The proposed method can be used to improve the quality of products in textile industry. We first develop a mathematical model of the AC servo motor and yarn tension system. Based on the results of the mathematical model, an IMC PID controller is designed to control the microtension of the yarn. The proposed IMC-PID controller can be directly calculated from the time constant and time delay. Feedforward control is used to compensate for the linear velocity of the winding roller. To reduce the lateral vibrations of the yarn, we designed an active roller to nip the moving yarn. The active roller compensates for the variation in the diameter of the unwinding roller. The proposed method effectively improves the dynamics performance and the robustness of the system, and is appropriate for industrial application. Experimental instruments, including a tension sensor, an AC servo motor and a motion controller, equipped with a computer, are used to test the proposed method. The simulation and experimental results show the effectiveness of the proposed controller for the yarn microtension control system.

Low‐power non‐ideal pulse‐width modulated DC–DC buck–boost converter: design, analysis and experimentation

In this study, parasitic elements (non-idealities) effect on a low-power DC-DC buck-boost converter design is analysed and investigation is carried out by both large (i.e. steady-state) and small signal analysis. The large signal analysis of non-ideal buck-boost converter explored the significant information such as nearly accurate duty cycle, maximum allowable duty cycle and maximum possible output voltage. Further, accurate mathematical design formulae are derived of inductor and capacitor for specified inductor current ripple and output voltage ripple (OVR), respectively. Moreover, consequences of different equivalent series resistance of capacitor on OVR is examined. Subsequently, the exact model of buck-boost converter is procured from the small signal analysis, which is almost analogous to practical system. In order to show the impact of non-idealities on controller design, an internal model control PID controller is designed for ideal, semi-non-ideal and complete non-ideal systems based on their respective models, which shows the controller based on non-ideal model provides very close results to practical system. Conclusively, the complete theoretical explorations are justified by simulations and substantiated by experimental results.

Tuning of PID Controller Based on Phase Margin for Stable Processes Via IMC Principles

A novel IMC (internal model control) PID tuning method is proposed for stable processes with time delay in the frequency domain. In the paper, the IMC controller is originally transformed into a classical feedback PID controller without approximating the time delay. The phase margin is used for an analytical approach of selecting controller parameter which is directly related to the dynamic performance and robustness of the system in IMC. The resulting analytical IMC-PID controller achieves almost the same control effect as IMC controller.

IMC PID controller tuning for stable and unstable processes with time delay

In this paper, a new internal model control (IMC) PID tuning method is proposed for stable and unstable processes with time delay. In order to implement pole zero conversion and guarantee the stability of the process, an imaginary first-order filter based on pole zero conversion is considered for the stable and unstable first order processes with time delay and a first-order lead-lag compensator is serried to PID controller for first order plus integrating and second order unstable processes with time delay. Set-point weighting is used to reduce the undesirable overshoot. The adjusting parameter can be calculated by the time constant and time delay of the processes directly, and the guidelines to calculate the coefficients have high oneness in form. Simulation works have been performed and compared with recently reported method, and the proposed tuning method gives consistently better performance and robustness for a class of processes with time delay.

Design and Simulation of Internal Model Controller for a Real Time Nonlinear Process

Background/Objectives: PID controllers are one of the first solutions often considered in the control of process industries. It has always been very difficult to treat the level anomalies n the real time processes. Particularly the non linear systems and processes have been a challenge in relation with their dynamics and flow properties. Methods/Statistical analysis: Dual Spherical Tank Liquid Level System (DSTLLS) has the characteristics of nonlinearity due to the dynamic behaviour and area of cross section of tank. One of the major problems in process industries is to control of liquid level for Second Order System Plus Delay (SOSPD) system because the presence of time delay in the system can lead to destabilization of the system. This simulation aims at portraying the performance of the designed Internal Model Control (IMC) PID Controller. Using the black box modelling technique the SOSPD is mathematically modelled experimentally, assuming the system to be a Single Input Single Output (SISO) model. Findings: The aim of this paper is to design a PID controller using IMC tuning method for a (DSTLLS) whose modelling has been done in real time. This simulation briefly explains about stabilizing problem for SOSPD system using an IMC PID controller. The designed controller performance is analysed in terms of performance indices like Integral Squared Error (ISE) and Integral Absolute Error (IAE) and time domain specifications like Rise time, Settling time and Peak time. Conclusion: The validation of the performance of the designed controller is performed under MATLAB environment. There can different controllers which can be also experimented on the same mathematical model for different configurations of the system, namely MISO and MIMO.

Maximum sensitivity based fractional IMC–PID controller design for non-integer order system with time delay

A simple approach with a small number of tuning parameters is a key goal in fractional order controller design. Recently there have been a number of limited attempts to bring about improvements in these areas. In this paper, a new design method for a fractional order PID controller based on internal model control (IMC) is proposed to handle non-integer order systems with time delay. In order to reduce the number of tuning parameters and mitigate the impact of time delay, the fractional order internal model control scheme is used. Considering the robustness of the control system with respect to process variations and model uncertainty, maximum sensitivity is applied to the tuning of the parameters. The resulting controller has the structure of a fractional order PID which is cascaded with a filter. This is named a fractional IMC–PID controller. Numerical results are given to show the efficiency of the proposed controller.

The design of an IMC-PID controller based on MEOTF and its application to non-square processes with time delay

It is difficult to design a controller directly for non-square multi-variable systems with time delay. In the current paper, we propose a new design method for an Internal Model Control PID controller based on a modified effective open-loop transfer function (MEOTF) for non-square processes with time delay. The MEOTF method is used to decompose the complex non-square process into several equivalent independent single-input/single-output processes. Using the Taylor Particle Swarm Optimisation (Taylor-PSO) model reduction method, the MEOTF of the non-square process is approximated by a reduced order form. The reduced form of the MEOTF is then used to design the Internal Model Control PID controller, which is then used for the original non-square process. To improve the robust stability, a first-order filter is added in the feedback loop. Finally, we present simulation results showing the validity and reliability of this method. In particular, our method has a strong anti-interference characteristic and retains its good control performance in the presence of model perturbation and interference.

Design of a robust internal model control PID controller based on linear quadratic gaussian tuning strategy

A design procedure of the robust IMC‐PID controller based on the linear quadratic Gaussian (LQG) tuning strategy is proposed to avoid the cut‐and‐try method in tuning the internal model control proportional integral derivative (IMC‐PID) controller parameters. In this paper, the relationship between the optimal controller and the maximum sensitivity function is established. Then the relationship between the maximum sensitivity function and the IMC‐PID parameter is established. The IMC‐PID parameter can be tuned by the above two relationships. In other words, the tuned IMC‐PID parameter depends on the optimal controller parameter which is designed by the LQG tuning strategy. The application to design a process of the IMC‐PID controller shows the effectiveness of the proposed approach for the first order plus the dead time (FOPDT) system and the second order plus the dead time (SOPDT) system. Simulation results present that the proposed method shows the tradeoff between the dynamic performance and the system robustness.

IMC-PID tuning method based on sensitivity specification for process with time-delay

To overcome the deficiencies addressed in the conventional PID control and improve the dynamic performance and robustness of the system, a simple design and parameters tuning approach of internal model control-PID (IMC-PID) controller was proposed for the first order plus time-delay (FOPTD) process and the second order plus time-delay (SOPTD) process. By approximating the time-delay term of the process model with the first-order Taylor series, the expressions for IMC-PID controller parameters were derived, and they had only one adjustable parameter λ which was directly related to the dynamic performance and robustness of the system. Moreover, an analytical approach of selecting λ was given based on the maximum sensitivity Ms. Then, the robust tuning of the system could be achieved according to the value of Ms. In addition, the proposed method could be extended to the integrator plus time-delay (IPTD) process and the first order delay integrating (FODI) process. Simulation studies were carried out on various processes with time-delay, and the results show that the proposed method could provide a better dynamic performance of both the set-point tracking and disturbance rejection and robustness against parameters perturbation.

Dynamics and control designs for internal thermally coupled distillation columns with different purities, Part 2 : close loop analysis and control designs*

Abstract Interaction between overhead and bottom composition loops of internal thermally coupled distillation columns (ITCDIC) with four purities are analyzed by means of relative gain array, condition number and singular value decomposition, which indicates that high and very high-purity ITCDIC are well coupled and ill-conditioned systems with severe gain directionality problem. Based on the above dynamic behaviors, suitable control schemes of four different purity systems are studied. In low-purity system, internal model control (IMC) is better than decentralized proportion integral differential (D-PID) control in terms of response speed and remaining errors. In moderate-purity system, D-PID can effectively reject large load disturbances while IMC fails due to severe mismatch between model and plant. In high-purity system, neither IMC nor D-PID can provide satisfactory control so that modified IMC and multivariable PID with singular value decomposition scheme are presented respectively to improve contro...

Dynamics and Control of High Purity Heat Integrated Distillation Columns

The dynamic behaviors of a high purity internal thermally coupled distillation column (ITCDIC) are studied. It is observed that these dynamic behaviors are characterized by high sensitivity to disturbances, strong asymmetric nonlinearity, and a distinct inverse response, which all cause an increased mismatch between the linear model and the real plant. Investigation on the interaction between overhead and bottom composition loops indicates that a high purity ITCDIC is an ill-conditioned system with a gain directionality problem. Internal model control (IMC) and multiloop proportional, integral, and derivative (PID) control are explored in this study. Modified IMC and multivariable PID control with singular value decomposition are also presented to further the improvement of control performance and guarantee smooth operation of the high purity ITCDIC.