10,596 research outputs found
On the Selection of Tuning Methodology of FOPID Controllers for the Control of Higher Order Processes
In this paper, a comparative study is done on the time and frequency domain
tuning strategies for fractional order (FO) PID controllers to handle higher
order processes. A new fractional order template for reduced parameter modeling
of stable minimum/non-minimum phase higher order processes is introduced and
its advantage in frequency domain tuning of FOPID controllers is also
presented. The time domain optimal tuning of FOPID controllers have also been
carried out to handle these higher order processes by performing optimization
with various integral performance indices. The paper highlights on the
practical control system implementation issues like flexibility of online
autotuning, reduced control signal and actuator size, capability of measurement
noise filtration, load disturbance suppression, robustness against parameter
uncertainties etc. in light of the above tuning methodologies.Comment: 27 pages, 10 figure
Depth of anesthesia control using internal model control techniques
The major difficulty in the design of closed-loop control during anaesthesia is the inherent patient variability due to differences in demographic and drug tolerance. These
discrepancies are translated into the pharmacokinetics (PK),
and pharmacodynamics (PD). These uncertainties may affect
the stability of the closed loop control system. This paper aims at developing predictive controllers using Internal Model Control technique. This study develops patient dose-response models and to provide an adequate drug administration regimen for the anaesthesia to avoid under or over dosing of the patients. The controllers are designed to compensate for patients inherent drug response variability, to achieve the best output disturbance rejection, and to maintain optimal set point response. The results are evaluated compared with traditional PID controller and the performance is confirmed in our
simulation
Optimum Weight Selection Based LQR Formulation for the Design of Fractional Order PI{\lambda}D{\mu} Controllers to Handle a Class of Fractional Order Systems
A weighted summation of Integral of Time Multiplied Absolute Error (ITAE) and
Integral of Squared Controller Output (ISCO) minimization based time domain
optimal tuning of fractional-order (FO) PID or PI{\lambda}D{\mu} controller is
proposed in this paper with a Linear Quadratic Regulator (LQR) based technique
that minimizes the change in trajectories of the state variables and the
control signal. A class of fractional order systems having single non-integer
order element which show highly sluggish and oscillatory open loop responses
have been tuned with an LQR based FOPID controller. The proposed controller
design methodology is compared with the existing time domain optimal tuning
techniques with respect to change in the trajectory of state variables,
tracking performance for change in set-point, magnitude of control signal and
also the capability of load disturbance suppression. A real coded genetic
algorithm (GA) has been used for the optimal choice of weighting matrices while
designing the quadratic regulator by minimizing the time domain integral
performance index. Credible simulation studies have been presented to justify
the proposition.Comment: 6 pages, 5 figure
Control of open-loop unstable processes with time delay using PI/PID controllers specified using tuning rules: An outline survey
The ability of PI and PID controllers to compensate many practical processes has led to their wide acceptance in industrial applications. The requirement to choose two or three controller parameters is conveniently done using tuning rules. Starting with a general discussion of industrial practice, the paper provides a survey of tuning rules for continuous time PI and PID control of open-loop unstable time-delayed single-input, single-output (SISO) processes
Improved cascade control structure for enhanced performance
In conventional single feedback control, the corrective action for disturbances does not begin until the controlled variable deviates from the set point. In this case, a cascade control strategy can be used to improve the performance of a control system particularly in the presence of disturbances. In this paper, an improved cascade control structure and controller design based on standard forms, which was initially given by authors, is suggested to improve the performance of cascade control. Examples are given to illustrate the use of the proposed method and its superiority over some existing design methods
A Conformal Mapping Based Fractional Order Approach for Sub-optimal Tuning of PID Controllers with Guaranteed Dominant Pole Placement
A novel conformal mapping based Fractional Order (FO) methodology is
developed in this paper for tuning existing classical (Integer Order)
Proportional Integral Derivative (PID) controllers especially for sluggish and
oscillatory second order systems. The conventional pole placement tuning via
Linear Quadratic Regulator (LQR) method is extended for open loop oscillatory
systems as well. The locations of the open loop zeros of a fractional order PID
(FOPID or PI{\lambda}D{\mu}) controller have been approximated in this paper
vis-\`a-vis a LQR tuned conventional integer order PID controller, to achieve
equivalent integer order PID control system. This approach eases the
implementation of analog/digital realization of a FOPID controller with its
integer order counterpart along with the advantages of fractional order
controller preserved. It is shown here in the paper that decrease in the
integro-differential operators of the FOPID/PI{\lambda}D{\mu} controller pushes
the open loop zeros of the equivalent PID controller towards greater damping
regions which gives a trajectory of the controller zeros and dominant closed
loop poles. This trajectory is termed as "M-curve". This phenomena is used to
design a two-stage tuning algorithm which reduces the existing PID controller's
effort in a significant manner compared to that with a single stage LQR based
pole placement method at a desired closed loop damping and frequency.Comment: 23 pages, 7 figures, in press; Communications in Nonlinear Science
and Numerical Simulations, 201
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