Showing papers on "PID controller published in 2004"

A particle swarm optimization approach for optimum design of PID controller in AVR system

Abstract: In this paper, a novel design method for determining the optimal proportional-integral-derivative (PID) controller parameters of an AVR system using the particle swarm optimization (PSO) algorithm is presented. This paper demonstrated in detail how to employ the PSO method to search efficiently the optimal PID controller parameters of an AVR system. The proposed approach had superior features, including easy implementation, stable convergence characteristic, and good computational efficiency. Fast tuning of optimum PID controller parameters yields high-quality solution. In order to assist estimating the performance of the proposed PSO-PID controller, a new time-domain performance criterion function was also defined. Compared with the genetic algorithm (GA), the proposed method was indeed more efficient and robust in improving the step response of an AVR system.

PID vs LQ control techniques applied to an indoor micro quadrotor

Abstract: The development of miniature flying robots has become a reachable dream, thanks to the new sensing and actuating technologies. Micro VTOL systems represent a useful class of flying robots because of their strong abilities for small-area monitoring and building exploration. In this paper, we present the results of two model-based control techniques applied to an autonomous four-rotor micro helicopter called quadrotor. A classical approach (PID) assumed a simplified dynamics and a modern technique (LQ) based on a more complete model. Various simulations were performed and several tests on the bench validate the control laws. Finally, we present the results of the first test in flight with the helicopter released. These developments are part of the OS4 project in our lab.

Simple analytic rules for model reduction and PID controller tuning

Abstract: The aim of this paper is to present analytic rules for PID controller tuning that are simple and still result in good closed-loop behavior. The starting point has been the IMC-PID tuning rules that have achieved widespread industrial acceptance. The rule for the integral term has been modified to improve disturbance rejection for integrating processes. Furthermore, rather than deriving separate rules for each transfer function model, there is a just a single tuning rule for a first-order or second-order time delay model. Simple analytic rules for model reduction are presented to obtain a model in this form, including the 'half rule' for obtaining the effective time delay.

Development of a biomimetic robotic fish and its control algorithm

Abstract: This paper is concerned with the design of a robotic fish and its motion control algorithms. A radio-controlled, four-link biomimetic robotic fish is developed using a flexible posterior body and an oscillating foil as a propeller. The swimming speed of the robotic fish is adjusted by modulating joint's oscillating frequency, and its orientation is tuned by different joint's deflections. Since the motion control of a robotic fish involves both hydrodynamics of the fluid environment and dynamics of the robot, it is very difficult to establish a precise mathematical model employing purely analytical methods. Therefore, the fish's motion control task is decomposed into two control systems. The online speed control implements a hybrid control strategy and a proportional-integral-derivative (PID) control algorithm. The orientation control system is based on a fuzzy logic controller. In our experiments, a point-to-point (PTP) control algorithm is implemented and an overhead vision system is adopted to provide real-time visual feedback. The experimental results confirm the effectiveness of the proposed algorithms.

PID Controllers for Time Delay Systems

Abstract: Preface Introduction The Hermite-Biehler Theorem and Its Generalization PI Stabilization of Delay-Free Linear Time-Invariant Systems PID Stabilization of Delay-Free Linear Time-Invariant Systems Preliminary Results for Analyzing Systems with Time Delay Stabilization of Time-Delay Systems Using a Constant Gain Feedback Controller PI Stabilization of First-Order Systems with Time Delay PID Stabilization of First-Order Systems with Time Delay Control System Design Using the PID Controller Analysis of Some PID Tuning Techniques PID Stabilization of Arbitrary Linear Time-Invariant Systems with Time Delay Algorithms for Real and Complex PID Stabilization A Proof of Lemmas 8.3, 8.4, and 8.5 B Proof of Lemmas 8.7 and 8.9 C Detailed Analysis of Example 11.4 References Index

Tuning of PID Controllers Based on Bode's Ideal Transfer Function

Abstract: This paper presents a new strategy for tuning PID controllers based on a fractional reference model. The model is represented as an ideal closed-loop system whose open-loop is given by the Bode’s ideal transfer function. The PID controller parameters are determined by the minimization of the integral square error (ISE) between the time responses of the desired fractional reference model and of the system with the PID controller. The resulting closed-loop system (with the PID controller) has the desirable feature of being robust to gain variations with step responses exhibiting an iso-damping property. Several examples are presented that demonstrate the effectiveness and validity of the proposed methodology.

Attitude stabilization of a four-rotor aerial robot

Abstract: In this paper, we propose a quaternion-based feedback control scheme for exponential attitude stabilization of a four-rotor vertical take-off and landing (VTOL) aerial robot known as the quadrotor aircraft. The proposed controller is based upon the compensation of the Coriolis and gyroscopic torques and the use of a PD/sup 2/ feedback structure, where the proportional action is in terms of the quaternion vector and the two derivative actions are in terms of the airframe angular velocity and the quaternion velocity. We also show that the model-independent PD controller, where the proportional action is in terms of the quaternion vector and the derivative action is in terms of the airframe angular velocity, without compensation of the Coriolis and gyroscopic torques, provides asymptotic stability for our problem. Simulation results are also provided to show the effectiveness of the proposed controller.

On Fractional PIλ Controllers: Some Tuning Rules for Robustness to Plant Uncertainties

Abstract: The objective of this work is to find out optimum settings for a fractional PIλ controller in order to fulfill three different robustness specifications of design for the compensated system, taking advantage of the fractional order, λ. Since this fractional controller has one parameter more than the conventional PI controller, one more specification can be fulfilled, improving the performance of the system and making it more robust to plant uncertainties, such as gain and time constant changes. For the tuning of the controller an iterative optimization method has been used, based on a nonlinear function minimization. Two real examples of application are presented and simulation results are shown to illustrate the effectiveness of this kind of unconventional controllers.

Gain scheduler middleware: a methodology to enable existing controllers for networked control and teleoperation - part I: networked control

Abstract: Conventionally, in order to control an application over a data network, a specific networked control or teleoperation algorithm to compensate network delay effects is usually required for controller design. Therefore, an existing controller has to be redesigned or replaced by a new controller system. This replacement process is usually costly, inconvenient, and time consuming. In this paper, a novel methodology to enable existing controllers for networked control and teleoperation by middleware is introduced. The proposed methodology uses middleware to modify the output of an existing controller based on a gain scheduling algorithm with respect to the current network traffic conditions. Since the existing controller can still be utilized, this approach could save much time and investment cost. Two examples of the middleware applied for networked control and teleoperation with IP network delays are given in these two companion papers. Part I of these two companion papers introduces the concept of the proposed middleware approach. Formulation, delay modeling, and optimal gain finding based on a cost function for a case study on DC motor speed control with a proportional-integral (PI) controller are also described. Simulation results of the PI controller shows that, with the existence of IP network delays, the middleware can effectively maintain the networked control system performance and stabilize the system. Part II of this paper will cover the use of the proposed middleware concept for a mobile robot teleoperation.

Method and system for wireless group communications

Abstract: A method for wireless communication between a controller and a group of user devices, each user device having a respective identification number (RFID), comprising: assigning a sequence number (PID) to each user device; transmitting the PID from the controller to each user device; and, in response to a message broadcast from the controller to the group of user devices, receiving a response from each user device in sequence, wherein each response includes the respective PID of the user device, and wherein each user device determines when to transmit its response by comparing its PID with the PID of each transmitted response. The method supports group identification, middle stream devices, multifunction user devices (e.g., remote control, wireless mouse, motion detector), and remote programming of user devices and middle stream devices. Also, a matching method is provided for comparing a sample item to a reference item using the controller and user devices.

Synergetic control of power converters for pulse current charging of advanced batteries from a fuel cell power source

Abstract: This paper presents a synergetic controller for pulse current charging of advanced batteries from a fuel cell power source. Pulse current charging protocol that has been shown to have many advantages over the traditional constant current/constant voltage protocol is applied in a fuel cell powered battery-charging station to reduce the total charging time. Strong nonlinearity and dynamics exist in such systems. In this paper, the synergetic control approach is applied to regulate the buck converters that control the pulse charging currents to the many batteries. A practical synergetic controller to coordinate pulse current charging of the battery is synthesized and discussed. It provides asymptotic stability with respect to the required operating modes, invariance to load variations, and robustness to variation of the input and converter parameters. The synergetic controller is then implemented in Simulink. The dynamic characteristics of the synergetic controller are studied and compared with PI controller by conducting system simulation and experimental tests. Simulation and experiment results show the synergetic controller is robust for such nonlinear dynamic system and achieves better performance than the standard PI controller.

Robust decentralised load-frequency control using an iterative linear matrix inequalities algorithm

Abstract: The load-frequency control (LFC) problem has been one of the major subjects in electric power system design/operation and is becoming much more significant today in accordance with increasing size, changing structure and complexity of interconnected power systems. In practice LFC systems use simple proportional-integral (PI) controllers. However, since the PI controller parameters are usually tuned based on classical or trial-and-error approaches, they are incapable of obtaining good dynamical performance for a wide range of operating conditions and various load changes scenarios in a multi-area power system. For this problem, the decentralised LFC synthesis is formulated as an HN-control problem and is solved using an iterative linear matrix inequalities algorithm to design of robust PI controllers in the multi-area power systems. A three-area power system example with a wide range of load changes is given to illustrate the proposed approach. The resulting controllers are shown to minimise the effect of disturbances and maintain the robust performance. List of symbols Dfi frequency deviation DPgt governor valve position DPci governor load setpoint DPti turbine power DPtiei net tie-line power flow DPdi area load disturbance

Wiener model identification and predictive control of a pH neutralisation process

Abstract: Wiener model identification and predictive control of a pH neutralisation process is presented. Input-output data from a nonlinear, first principles simulation model of the pH neutralisation process are used for subspace-based identification of a black-box Wiener-type model. The proposed nonlinear subspace identification method has the advantage of delivering a Wiener model in a format which is suitable for its use in a standard linear-model-based predictive control scheme. The identified Wiener model is used as the internal model in a model predictive controller (MPC) which is used to control the nonlinear white-box simulation model. To account for the unmeasurable disturbance, a nonlinear observer is proposed. The performance of the Wiener model predictive control (WMPC) is compared with that of a linear MPC, and with a more traditional feedback control, namely a PID control. Simulation results show that the WMPC outperforms the linear MPC and the PID controllers.

Performance Evaluation of Two Published Closed-loop Control Systems Using Bispectral Index Monitoring: A Simulation Study

Abstract: Background. Although automated closed-loop control systems may improve quality of care, their safety must be proved under extreme control conditions. This study describes a simulation methodology to test automated controllers and its application in a comparison of two published controllers for Bispectral Index (BIS)-guided propofol administration. Methods: A patient simulator was developed to compare controllers. Using input scripts to dictate patient characteristics, target BIS values, and the time course of surgical events, the simulator continuously monitors the infusion pump under control and generates BIS values as a composite of modeled response to drug, perceived stimulation, and random noise. The simulator formats the output stream of BIS data as input to the controller under test to emulate the serial output of the actual BIS monitor. A published model-based controller and a classic proportional integral derivative controller were compared when using the BIS value as a controlled variable. Each controller was tested using a set of 10 virtual patients undergoing a fixed surgical profile that was repeated with BIS targets set at 30, 50, and 70. Controller performance was assessed using median (absolute) prediction error, divergence, wobble, and percentage time within BIS target range metrics. Results: The median prediction error was significantly smaller for the proportional integral derivative controller than for the model-based controller. The median absolute prediction error was smaller for the model-based controller than for the proportional integral derivative controller for each BIS target, reaching statistical significance for targets 30 and 50. Conclusions: When simulating closed-loop control of BIS using propofol, the use of a patient-individualized, model-based adaptive closed-loop system with effect site control resulted in better control of BIS compared with a standard proportional integral derivative controller with plasma site control. Even under extreme conditions, the modeled-based controller exhibited no behavioral problems.

Development of a self-tuned neuro-fuzzy controller for induction motor drives

Abstract: In This work a novel adaptive neuro-fuzzy (NF) based speed control of an induction motor (IM) is presented. The proposed neuro-fuzzy controller (NFC) incorporates fuzzy logic laws with a five-layer artificial neural network (ANN) scheme. In this controller only three membership functions are used for each input keeping in mind for low computational burden, which will be suitable for real-time implementation. Furthermore, for the proposed NFC an improved self-tuning method is developed based on the IM theory and its high performance requirements. The main task of the tuning method is to adjust the parameters of the fuzzy logic controller (FLC) in order to minimize the square of the error between actual and reference outputs. This work also demonstrates how the proposed NFC can easily be adjusted to work with different size of induction motors. A complete simulation model for indirect field oriented control of IM incorporating the proposed NFC is developed. The performance of the proposed NFC based IM drive is investigated extensively at different operating conditions in simulation. In order to prove the superiority of the proposed NFC, the results for the proposed controller are also compared to those obtained by a conventional PI controller. The proposed NFC based IM drive is found to be more robust as compared to conventional PI controller based drive and hence found suitable for high performance industrial drive applications.

An electronic throttle control strategy including compensation of friction and limp-home effects

Abstract: An electronic throttle is a low-power dc servo drive which positions the throttle plate. Its application in modern automotive engines leads to improvements in vehicle drivability, fuel economy, and emissions. Transmission friction and the return spring limp-home nonlinearity significantly affect the electronic throttle performance. The influence of these effects is analyzed by means of computer simulations, experiments, and analytical calculations. A dynamic friction model is developed in order to adequately capture the experimentally observed characteristics of the presliding-displacement and breakaway effects. The linear part of electronic throttle process model is also analyzed and experimentally identified. A nonlinear control strategy is proposed, consisting of a proportional-integral-derivative (PID) controller and a feedback compensator for friction and limp-home effects. The PID controller parameters are analytically optimized according to the damping optimum criterion. The proposed control strategy is verified by computer simulations and experiments.

Optimal PID speed control of brush less DC motors using LQR approach

Abstract: A novel optimal PID control design is proposed in this paper. The methodology of linear quadratic regulator is utilized to search the optimal parameters of the PID controller. The augmented state vector of performance measure involves output signals only. The weighting functions are determined through poles assignment. The existence criteria of the optimal PID controller are derived. The new PID tuning algorithm is applied to the speed control of BLDC motors. Computer simulations and experimental results show that the performance of the optimal PID controller is better than that of the traditional PID controller.

On the gain scheduling for networked PI controller over IP network

Abstract: The potential use of networks for real-time high-performance control and automation is enormous and appealing. Replacing a widely used proportional-integral (PI) controller by a new networked controller for networked control capability can be costly and time-consuming. This paper proposes a methodology based on gain scheduling with respect to real-time IP traffic conditions to enhance the existing PI controller so it can be used over IP networks with a general network protocol like Ethernet. This paper first describes the gain scheduling approach based on constant network delays using a rational function approach. The formulation is extended to random IP network round-trip time (RTT) delays by using the generalized exponential distribution model. Simulation results show that the PI controller with gain scheduling provides significantly better networked control system performance.

Model predictive control of integrated unit operations: Control of a divided wall column

Abstract: The integration of several unit operations into one common apparatus (process intensification) has the potential to substantially improve the economics of chemical processes if applied to adequate problems. On the other hand, the integration typically causes strong interactions of different process quantities and a loss in degrees of freedom. This may require a more elaborate automatic control scheme. In this study, the control of a divided wall column has been investigated in comparison to the control with a single loop PI controller concept. Although the PI controller concept can be implemented successfully, the model predictive controller shows a considerably improved control behaviour in respect to maximum deviations of the controlled variables and the time to reach steady state.

A New Approach to Parameter Tuning of Controllers by Using One-Shot Experimental Data-A Proposal of Fictitious Reference Iterative Tuning

Abstract: In this paper, we propose one of the powerful iterative tuning methods for the parameters of the controller of a closed loop system. The method we provide here requires only one-shot experiment and then an iterative non-linear optimization for obtaining the optimum parameters of the controller can be performed off-line by using the fictitious reference signal computed by the first experimental data (from this reason, we refer to our method as “fictitious reference iterative tuning”, which is abbreviated to “FRIT”). The main concept and the algorithm of FRIT are provided as our main results of this paper. Moreover, we give a control experiment of the cart-system in order to show the validity of FRIT.