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Showing papers on "PID controller published in 1997"


Journal ArticleDOI
TL;DR: In this article, a model-based adaptive friction compensation on a DC motor servomechanism is proposed to deal with structured normal forces and temperature variations, assuming that a nominal friction model is known and that the friction variations can be suitably structured.
Abstract: This paper illustrates the application of a model-based adaptive friction compensation on a DC motor servomechanism. The dynamic friction model and the control structure studied previously by the authors were used as a basis for this study. The paper first proposes a two-step off-line method to estimate the nominal static and dynamic parameters associated with the model. Then two adaptive globally stable mechanisms are introduced to deal with structured normal forces and temperature variations. Assuming that a nominal friction model is known and that the friction variations can be suitably structured, adaptation is performed on the basis of only one parameter. The paper presents experimental results validating the identification of the dynamic friction model and the adaptive control scheme. These results show that the adaptive loop improves over a fixed compensation scheme and over a PID controller without friction compensation. © 1997 by John Wiley & Sons, Ltd.

466 citations


Journal ArticleDOI
TL;DR: In this article, a generalized Preisach model is proposed to relax the congruency requirement on the hysteresis loops of a piezoceramic actuator.
Abstract: This paper presents a new approach for modeling the hysteresis nonlinearity of a piezoceramic actuator using a modified generalized Preisach model, and the use of this model in a linearizing control scheme. The developed generalized Preisach model relaxes the congruency requirement on the hysteresis loops of a piezoceramic actuator, which must be satisfied when using the classical Preisach model. The congruency property is experimentally proved to not hold when running the actuator on a minor hysteresis loop. A numerical expression of the model is derived in terms of first- and second-order reversal curve experimental datasets. Output prediction using this model is performed on both an exponentially decayed sinusoidal input signal and an arbitrary input signal, and the results show that the model can accurately reproduce the hysteresis response with an error of less than 2.7%. A tracking control system for a piezoceramic actuator is also developed by combining a PID feedback controller with a hysteresis linearizing scheme in a feed-forward loop. The results show that this new control system can achieve 0.25 μm tracking control accuracy, which is 80 and 50% less than that obtained when using an open-loop controller and a regular feedback control system, respectively.

368 citations


Journal ArticleDOI
20 Apr 1997
TL;DR: In this article, a position-controlled pneumatic actuator with a pulse width modulation (PWM) valve pulsing algorithm is described, which allows on/off solenoid valves to be used in place of costly servo valves.
Abstract: The development of a fast, accurate, and inexpensive position-controlled pneumatic actuator that may be applied to a variety of practical positioning applications is described. A novel pulse width modulation (PWM) valve pulsing algorithm allows on/off solenoid valves to be used in place of costly servo valves. The open-loop characteristic is shown both theoretically and experimentally to be near symmetrical. A comparison of the open- and closed-loop responses of standard PWM techniques and that of the novel PWM technique shows that there has been a significant improvement in the control. A linear process model is obtained from experimental data using system identification. A proportional integral derivative controller with added friction compensation and position feedforward has been successfully implemented. A worst case steady-state accuracy of 0.21 mm was achieved with a rise time of 180 ms for step inputs from 0.11 to 64 mm. Following errors to 64-mm S-curve profiles were less than 2.0 mm. The controller is robust to a sixfold increase in the system mass. The actuator's overall performance is comparable to that achieved by other researchers using servo valves.

288 citations


Journal ArticleDOI
TL;DR: A method for auto-tuning fully cross-coupled multivariable PID controllers from decentralized relay feedback is proposed forMultivariable processes with significant interactions, where significant performance improvement over the existing tuning methods is demonstrated.

239 citations


Journal ArticleDOI
TL;DR: In this paper, an adaptive learning algorithm based on GA for automatic tuning of proportional, integral and derivative (PID) controllers in Heating Ventilating and Air Conditioning (HVAC) systems to achieve optimal performance is presented.

191 citations


Journal ArticleDOI
TL;DR: In this article, the authors present an easy-to-use and reliable tuning strategy for unconstrained SISO dynamic matrix control (DMC) and lays a foundation for extension to multivariable systems.
Abstract: This paper presents an easy-to-use and reliable tuning strategy for unconstrained SISO dynamic matrix control (DMC) and lays a foundation for extension to multivariable systems. The tuning strategy achieves set point tracking with minimal overshoot and modest manipulated input move sizes and is applicable to a broad class of open loop stable processes. The derivation of an analytical expression for the move suppression coefficient, λ, and its demonstration in a DMC tuning strategy is one of the significant contributions of this work. The compact form for the analytical expression for λ is achieved by employing a first order plus dead time (FOPDT) model approximation of the process dynamics. With tuning parameters computed, DMC is then implemented in the classical fashion using a dynamic matrix formulated from step response coefficients of the actual process. Just as the FOPDT model approximation has proved a valuable tool in tuning rules such as Cohen−Coon, ITAE, and IAE for PID implementations, the tunin...

182 citations


Journal ArticleDOI
TL;DR: Further opportunities for oscillation detection in the off-line analysis of ensembles of data from control loops are examined and operational signatures that indicate the cause of an oscillation are presented.

175 citations


Journal ArticleDOI
TL;DR: This paper presents the design and experiment of a fuzzy proportional integral derivative (PID) controller for a flexible-joint robot arm with uncertainties from time-varying loads, and convincingly demonstrated that fuzzy logic control can be used for flexible-Joint robot arms with uncertainties and it is quite robust.
Abstract: This paper presents the design and experiment of a fuzzy proportional integral derivative (PID) controller for a flexible-joint robot arm with uncertainties from time-varying loads. Experimental results have shown remarkable tracking performance of this fuzzy PID controller, and have convincingly demonstrated that fuzzy logic control can be used for flexible-joint robot arms with uncertainties and it is quite robust. In this paper, the fuzzy PID controller is first described briefly, using a simple and practical PD+I controller configuration. This configuration preserves the linear structure of the conventional PD+I controller, but has nonconstant gains: the proportional, integral, and derivative gains are nonlinear functions of their input signals, which have self-tuning (adaptive) capabilities in set-point tracking performance. Moreover, these variable gains make the fuzzy PID controller robust with faster response time and less overshoot than its conventional counterpart. The proposed design was tested using a flexible-joint robot arm driven by a DC motor in a laboratory, where the arm was experienced with time-varying loads. Control performance by the conventional and fuzzy PID controllers for such a laboratory robotic system are both included in this paper for comparison.

161 citations


Proceedings ArticleDOI
04 Jun 1997
TL;DR: In this paper, the authors provide a computationally constructive characterization of all stabilizing PID controllers that stabilize a given plant, which is an extension of the YJBK characterization restricted to PIDs and opens up the possibility of optimal design using PIDs.
Abstract: The YJBK parametrization characterizes all stabilizing controllers. In industry, most controllers are PID and there is no solution to the problem: can a plant P(s) be stabilized by a PID controller? In this paper, we provide an answer to this question. Besides settling the question of existence, we provide a computationally constructive characterization of all stabilizing PID controllers that stabilize a given plant. Thus this result is essentially an extension of the YJBK characterization restricted to PIDs and opens up the possibility of optimal design using PIDs.

143 citations


Journal ArticleDOI
TL;DR: In this article, a PI controller with dead-time compensation is described, which is based on a Smith predictor structure plus the addition of a filter acting on the error between the output and its prediction in order to improve robustness.

140 citations


Journal ArticleDOI
01 Mar 1997
TL;DR: A neuro-control system was designed to control the knee joint to move in accordance with the desired trajectory of movement through stimulation of quadriceps muscle, and the neuro-PID controller showed promise as a position controller of knee joint angle withquadriceps stimulation.
Abstract: A neuro-control system was designed to control the knee joint to move in accordance with the desired trajectory of movement through stimulation of quadriceps muscle. This control system consisted of a neural controller and a fixed parameter proportional-integral-derivative (PID) feedback controller, which was designated as a neuro-PID controller. A multilayer feedforward time-delay neural network was used and trained as an inverse model of the functional electrical stimulation (FES)-induced quadriceps-lower leg system for direct feedforward control. The training signals for neural network learning were obtained from experimentation using a low-pass filtered random sequence to reveal the plant characteristics. The Nguyen-Widrow method was used to initialize the neural connection weights. The conjugate gradient descent algorithm was then used to modify these connection weights so as to minimize the errors between the desired outputs and the network outputs. The knee joint angle was controlled with only small deviations along the desired trajectory with the aid of the neural controller. In addition, the PID feedback controller was utilized to compensate for the residual tracking errors caused by disturbances and modeling errors. This control strategy was evaluated on one able-bodied and one paraplegic subject. The neuro-PID controller showed promise as a position controller of knee joint angle with quadriceps stimulation.

Journal ArticleDOI
TL;DR: In this paper, a noniterative procedure is suggested for identification of an arbitrarily chosen point in the third quadrant by the use of a two-channel relay, which consists of two relays operating in parallel on the process output and on the integral of process output, respectively.
Abstract: Tuning of feedback controllers for SISO systems often starts from information about the intersection of the Nyquist curve and the negative real axis. In standard autotuning this point is identified by a relay feedback experiment. For many processes, however, it would be advantageous to identify a point on the Nyquist curve somewhere in the third quadrant. The aim of this paper is two-fold. First, a noniterative procedure is suggested for identification of an arbitrarily chosen point in the third quadrant by the use of a two-channel relay. The two-channel relay consists of two relays operating in parallel on the process output and on the integral of the process output, respectively. Secondly, general a priori plant knowledge, often available, is utilized for the choice between PI and PID control and for amplitude-and-phase-margin based controller tuning.

Journal ArticleDOI
01 Sep 1997
TL;DR: In this article, the authors extended the frequency domain PID controller design method by presenting a comprehensive treatment of integrating processes and explicit PID tuning rules for integrating plus delay processes along with their associated gain and phase margins and allowable time delay variations.
Abstract: The paper extends the frequency domain PID controller design method, first proposed by the authors in an earlier paper, by presenting a comprehensive treatment of integrating processes. The general class of integrating processes is divided into two types, based on the sign of the second coefficient of the Taylor-series expansion applied to the stable part of the process transfer function. In both cases, the closed-loop performance is specified in terms of the desired control-signal trajectory scaled with respect to the magnitude of this coefficient. In addition, explicit PID tuning rules are given, for integrating plus delay processes along with their associated gain and phase margins and allowable time delay variations.

Journal ArticleDOI
TL;DR: An approach for tuning PID-type controllers is developed for single input single-output, linear time-invariant systems, based on an extension to the method of D-partition, which permits design for simultaneous minimum gain and phase margin requirements and allows design for specified maximum gain andphase cross-over frequencies of the controlled system.

Journal ArticleDOI
TL;DR: In this paper, an automatic tuning algorithm for decentralized PID control in multiple-input multiple-output (MIMO) plants is presented, which consists of two stages: the first stage identifies the desired critical point with almost no a priori information about the process and the second stage is used to tune the PID controllers by Ziegler-Nichols rules or their modifications.

Proceedings ArticleDOI
16 Jul 1997
TL;DR: A design method which determines PI/PID parameters of motion control systems based on genetic algorithms based on real-coded GAs with appropriate operators is presented and a synthesis method is proposed.
Abstract: In this paper a design method which determines PI/PID parameters of motion control systems based on genetic algorithms (GAs) is presented. First, a brief review is given of an analytical procedure to obtain optimal PI/PID parameters by minimization of the integral of time multiplied-squared error in the frequency domain. Next, a computationally simple procedure based on real-coded GAs with appropriate operators is described and a synthesis method is proposed. Simulation results are given which show the validation of the design method.

Journal ArticleDOI
01 Jul 1997
TL;DR: In this paper, a three-element structure, which is equivalent to a two-degrees-of-freedom control design, is proposed to synthesise a control system for an open-loop unstable process with time delay.
Abstract: To avoid performance limitations caused by an open-loop unstable pole, a three-element structure, which is equivalent to a two-degrees-of-freedom control design, is proposed to synthesise a control system for an open-loop unstable process with time delay. Through this proposed approach, control problems such as stabilising an unstable pole, servo-tracking and disturbance rejection can be treated independently. The resulting three-element structure can then be used to derive conventional two-degrees-of-freedom elements or conventional PID systems. Tuning rules for a PID controller are also provided. Examples are presented to illustrate the proposed method.

Patent
Tariq Samad1
02 Jun 1997
TL;DR: In this paper, an automatic tuner for control systems that produces as output values for parameters of an arbitrary controller is presented, where the controller is in a control loop so that its output effects changes in actuators and regulates a physical process.
Abstract: An automatic tuner for control systems that produces as output values for parameters of an arbitrary controller. The controller is in a control loop so that its output effects changes in actuators and regulates a physical process. The controller consists of either linear and nonlinear controller components or a combination of both. The tuner has a nonlinear approximator that has been optimized off-line. The off-line optimization is done without supervised learning so that desired outputs of neural network do not need to be available, and separate optimization to generate the desired outputs is not necessary. The off-line optimization can also rely on optimization criteria that are arbitrary: differentiability, convexity, even continuity of criteria are not required. The off-line optimization ensures robustness of generated controller parameters so that the input process characteristics do not need to be highly accurate. The off-line optimization is performed in such a way that the input parameters that relate to desired closed-loop system behavior include robustness parameters that can be used to effect tradeoffs between robust and nominal performance. The inputs to the nonlinear approximator consist of two sets of input parameters, either of which may be empty. A first set of input parameters can include parameters that relate to process characteristics. A second set of input parameters can include parameters that relate to desired closed-loop system behavior. The output values may be proportional and/or integral and/or derivative gains for PID-like controllers. The output values otherwise may be parameters for delay-compensation controllers, parameters for controllers that consist of lead-lag terms in combination with PID controllers, parameters for higher-order linear controllers, discrete variables that select between different control structures, or parameters for nonlinear controllers of predetermined structure. The nonlinear approximator may be implemented as a compositional sigmoidal mapping, a multilayer perception structure, a fuzzy logic model, a radial basis function network, a polynomial expansion, or other parametrized nonlinear structure.

Journal ArticleDOI
TL;DR: A gain and phase margin tuning formula is derived for PID control of a second-order plus dead time plant with under-damped step response and a self-tuning controller incorporating this PID tuning formula has been implemented and tested on a pilot plant.
Abstract: The effectiveness of the proportional-integral-derivative (PID) controller for plants with under-damped step response is not well understood. In practice, one may have to tune the PID controller manually through trial and error for such a plant. In this paper, a gain and phase margin tuning formula is derived for PID control of a second-order plus dead time plant with under-damped step response. A self-tuning controller incorporating this PID tuning formula has been implemented and tested on a pilot plant which consists of a hinged rectangular plate whose angular deflection from the vertical is controlled by an air stream generated by a variable speed fan. The results are given in the paper.

Journal ArticleDOI
TL;DR: In this article, a new PID controller for the position and trajectory control of pneumatic actuators based on the sliding mode control approach is proposed, which is simple, easy to implement, and robust to payload and parametric variations.
Abstract: Pneumatic robot manipulators are characterized by high-order, time-variant actuator dynamics, nonlinearities due to compressibility of air, external disturbances such as static and Coulomb friction, and wide range of payload variations. Conventional PID controllers suffer from problems of gain tuning under these conditions. In this paper, a new control algorithm is proposed for the position and trajectory control of pneumatic actuators based on the sliding mode control approach. The stability of motion is proved for the case of a linear, time-invariant switching surface. A disadvantage of using sliding mode control for third- and higher-order mechanical systems is the need for acceleration feedback. In this paper, to overcome this difficulty we propose the use of differential pressure. The proposed controller is simple, easy to implement, and robust to payload and parametric variations. The effectiveness of the new scheme for position and trajectory control is illustrated by experiments on an industrial piston-driven cylindrical actuator with proportional valves.

Journal ArticleDOI
TL;DR: In this article, a nonlinear adaptive controller with an extended Kalman filter is proposed for temperature control of semi-batch polymerization reactors, which is based on differential geometric concepts.

Journal ArticleDOI
TL;DR: In this article, a two-stage structure for the control of voltage is investigated using a closed loop reactive current controller whose reference is set by an outer voltage controller, and the use of a PI controller and a fuzzy logic PI controller is investigated.

Proceedings ArticleDOI
07 Jul 1997
TL;DR: In this article, a tracking control method for a piezoelectric actuator based on PID controller augmented with a feedback linearization loop based on the Maxwell slip model is presented.
Abstract: The hysteresis characteristic of piezoelectric actuators makes precise position control very difficult. In this study a tracking control method for a piezoelectric actuator based on PID controller augmented with a feedback linearization loop based on the Maxwell slip model is presented. Further, the controller design is extended to include a repetitive controller. Experiments were performed on a piezoelectric 2-axis linear positioner for tracking sinusoidal waveforms and circles. The experimental results show that the tracking control performance is noticeably improved by augmenting the PID controller with a feedback linearization loop and repetitive controller.

Patent
02 Jan 1997
TL;DR: In this article, a surge prevention control system for use with a dynamic compressor provides a multiple module controller (20) for operating an anti-surge valve (12) to bypass flow around the dynamic compressor (11).
Abstract: A surge prevention control system for use with a dynamic compressor (11) provides a multiple module controller (20) for operating an anti-surge valve (12) to bypass flow around the dynamic compressor (11). The multiple module controller (20) includes a PID control module (21) and a rate control module (40). The PID control module (21) controls the anti-surge valve (12) to control the operating point of the dynamic compressor about the surge control line (71). The rate control module (40) uses the rate of approach of the operating point to surge control line (71) as its process variable. In the event of high rate of approach, the rate control module (40) takes control of the anti-surge valve (12). The setpoint of the rate control module (40) is adjusted to open the anti-surge valve (12) to control the rate of approach to the surge control line (71) to minimize the overshoot of the PID control.

Journal ArticleDOI
TL;DR: The proposed design method can tune the multiloop controllers on-line and in real-time to meet specified system robustness and performance and can be easily combined with existing process identification techniques to implement self-tuning multILoop controllers.
Abstract: An analytical method of tuning multiloop proportional−integral−derivative controllers based on gain and phase margin specifications is presented in this paper. The proposed design method can tune the multiloop controllers on-line and in real-time to meet specified system robustness and performance. The design method can be easily combined with existing process identification techniques to implement self-tuning multiloop controllers.

Journal ArticleDOI
TL;DR: In this paper, the authors present an easy-to-use and reliable tuning strategy that enables the control practitioner to maintain MPC at peak performance with minimal effort, using an analytical expression that computes the move suppression coefficients and guidelines to select the additional adjustable parameters.
Abstract: Model predictive control (MPC) has established itself as the most popular form of advanced multivariable control in the chemical process industry. However, the benefits of this technology cannot be realized unless the controller can be operated with desirable performance for an extended period of time. The objective of this work is to present an easy-to-use and reliable tuning strategy that enables the control practitioner to maintain MPC at peak performance with minimal effort. A novel analytical expression that computes the move suppression coefficients, guidelines to select the additional adjustable parameters, and their demonstration in an overall tuning strategy are some of the significant contributions of this work. The compact form for the analytical expression that computes the move suppression coefficients is derived as a function of a first order plus dead time (FOPDT) model approximation of the process dynamics. With tuning parameters computed. MPC is then implemented in the classical fashion using an internal model formulated from step response coefficients of the actual process. Just as a FOPDT model approximation has proved a valuable tool in tuning rules such as Cohen-Coon. ITAE and IAE for PID implementations, the tuning strategy presented here is significant because it offers an analogous approach for multivariable MPC.

Journal ArticleDOI
TL;DR: The “small gain theorem” is employed to obtain a simple sufficient condition on the global BIBO stability for general stable and unstable nonlinear control systems that possess finite gains and under the control of this type of fuzzy PI controlers.
Abstract: In this paper, we analyze in detail the bounded-input/bounded-output BIBO stability of the nonlinear fuzzy proportional-integral PI control systems developed in Ying, Siler, and Buckley 1990. In this investigation, the “small gain theorem” is employed to obtain a simple sufficient condition on the global BIBO stability for general stable and unstable nonlinear control systems that possess finite gains and under the control of this type of fuzzy PI controlers. The derived sufficient condition provides a useful criterion for the design of such fuzzy PI control systems. In addition, we prove that in a conventional PI control system, if the linear PI controller is replaced by the nonlinear fuzzy PI controller, the stability of the resulting control system remains unchanged. This is true no matter the given process is linear or not. We will also derive some simple and explicit formulas for computing the fuzzy PI controller parameters, using only the proportional and integral gains of the corresponding conventional linear PI controller. This result makes the new sufficient condition very practical, because using these formulas one can always replace a conventional linear PI controller by a nonlinear fuzzy PI controller without altering the system stability, to obtain better control performance.

Journal ArticleDOI
TL;DR: A simple but efficient method for fully compensating for steady-state error, which is the main problem in a PD-like fuzzy logic control system, is proposed so that tuning for fuzzy logic rule bases is unnecessary.

Journal ArticleDOI
TL;DR: In this article, a simple on-line process identification and autotuning method for the integrating process is proposed, which uses only the process input and output to obtain a process transfer function directly, while other previous closed-loop identification methods require the information of the closed loop control structure.
Abstract: In this paper, first we analyze why the conventional PID controller is not suitable to control integrating processes mathematically and intuitively. To overcome its structural limitation, we add an internal feedback loop, which can convert the integrating process to an open-loop stable process. Second, we propose a new and simple on-line process identification and autotuning method for the integrating process. Here we use only the process input and output to obtain a process transfer function directly, while other previous closed-loop identification methods require the information of the closed-loop control structure. This identification method can be applied not only to integrating processes but also to all those encountered in chemical engineering processes which are open-loop stable or unstable. From simulation studies, we can recognize that, in spite of its simplicity, the proposed on-line process identification and autotuning method shows not only good model accuracy but also superior control perform...

Journal ArticleDOI
01 Oct 1997
TL;DR: Although the PI controller works very well for this task, the neural networks showed improved performance and the reinforcement learning agent, when combined with a PI controller, learned to augment the PI control output for the subset of states for which control can be improved.
Abstract: An accurate simulation of a heating coil is used to compare the performance of a proportional plus integral (PI) controller to the following schemes for learning improved control: a neural network trained to predict the steady-state output of the PI controller, a neutral network trained to minimize the n-step ahead error between the coil output and the set point, and a reinforcement learning agent trained to minimize the sum of the squared error over time. Although the PI controller works very well for this task, the neural networks showed improved performance. The reinforcement learning agent, when combined with a PI controller, learned to augment the PI control output for the subset of states for which control can be improved.