Proportional Plus Integral Plus Derivative Research Articles

Some investigations on fuzzy P + fuzzy I + fuzzy D controller for non-stationary process

The paper addresses the adaptive behaviour of parallel fuzzy proportional plus fuzzy integral plus fuzzy derivative (FP+FI+FD) controller. The parallel FP+FI+FD controller is actually a non-linear adaptive controller whose gain changes continuously with output of the process under control. Two non-stationary processes, whose characteristics change with time, are considered for simulation study. Simulation is performed using software LabVIEW?. The set-point tracking response of parallel FP+FI+FD is compared with conventional parallel proportional plus integral plus derivative (PID) controller, tuned with the Ziegler-Nichols (Z-N) tuning technique. Simulation results show that conventional PID controller fails to track the set-point and becomes unstable as the process changes its characteristic with time. But the parallel FP+FI+FD controller shows considerably much better set-point tracking response and does not deviate from steady state. Also, a huge spike is observed in the output of PID controller as the reference set-point and process parameters are changed, while the FP+FI+FD controller gives spike free control signal.

Artificial neural network based proportional plus integral plus derivative controller for a brushless DC position control system

Brushless DC (BLDC) motors are useful in applications such as process control, robotics, industrial automation, aerospace, electric vehicles etc. due to such advantages as the elimination of rotor losses and magnetizing current. Wider usage of BLDC motors demands optimum position control for high efficiency, accuracy and reliability. For an accurate position control, the estimation of moment of inertia and friction coefficient of the motor with load is essential. This paper incorporates the computation of the moment of inertia and friction coefficient of a BLDC motor with load at different load settings and emphasizes that load has an appreciable effect on the dynamic performance of the system. To obtain the optimum position control, a proportional plus integral plus derivative (PID) controller is employed and tuned using the PARR method. Artificial neural networks are used for computing the moment of inertia and friction coefficient of a BLDC motor with load and PID controller parameters at various load settings. Simulation results of the position control system are obtained at different load settings. From the results, it is evident that the PID controlled position control system responds to the desired position with minimum rise time, settling time and peak overshoot and is in dependent of load settings.

Neuro-PID Control for Electric Vehicle

In this paper we consider the neuro-control method and its application to control problems of an electric vehicle. The neuro-control methods adopted here is based on Proportional-plus-Integral-plus-Derivative (PID) control, which has been adopted to solve process control or intelligent control problems. In Japan about eighty four percent of the process industries have used the PID control. After deriving the self-tuning PID control scheme (neuro-PID) using the learning ability of the neural network, we will show the control results by using the speed and torque control of an electric vehicle.

Fuzzy PID Controllers Using FPGA Technique for Real Time DC Motor Speed Control

The design of intelligent control systems has become an area of intense research interest. The development of an effective methodology for the design of such control systems undoubtedly requires the synthesis of many concepts from artificial intelligence. The most commonly used controller in the industry field is the proportional-plus-integral-plus-derivative (PID) controller. Fuzzy logic controller (FLC) provides an alternative to PID controller, especially when the available system models are inexact or unavailable. Also rapid advances in digital technologies have given designers the option of implementing controllers using Field Programmable Gate Array (FPGA) which depends on parallel programming. This method has many advantages over classical microprocessors. In this research, A model of the fuzzy PID control system is implemented in real time with a Xilinx FPGA (Spartan-3A, Xilinx Company, 2007). It is introduced to maintain a constant speed to when the load varies.,The model of a DC motor is considered as a second order system with load variation as a an example for complex model systems. For comparison purpose, two widely used controllers “PID and Fuzzy” have been implemented in the same FPGA card to examine the performance of the proposed system. These controllers have been tested using Matlab/Simulink program under speed and load variation conditions. The controllers were implemented to run the motor as real time application under speed and load variation conditions and showed the superiority of Fuzzy-PID.

Design of a Fractional Order Phase Shaper for Iso-Damped Control of a PHWR Under Step-Back Condition

Phase shaping using fractional order (FO) phase shapers has been proposed by many contemporary researchers as a means of producing systems with iso-damped closed loop response due to a stepped variation in input. Such systems, with the closed loop damping remaining invariant to gain changes can be used to produce dead-beat step response with only rise time varying with gain. This technique is used to achieve an active step-back in a Pressurized Heavy Water Reactor (PHWR) where it is desired to change the reactor power to a pre-determined value within a short interval keeping the power undershoot as low as possible. This paper puts forward an approach as an alternative for the present day practice of a passive step-back mechanism where the control rods are allowed to drop during a step-back action by gravity, with release of electromagnetic clutches. The reactor under a step-back condition is identified as a system using practical test data and a suitable Proportional plus Integral plus Derivative (PID) controller is designed for it. Then the combined plant is augmented with a phase shaper to achieve a dead-beat response in terms of power drop. The fact that the identified static gain of the system depends on the initial power level at which a step-back is initiated, makes this application particularly suited for using a FO phase shaper. In this paper, a model of a nuclear reactor is developed for a control rod drop scenario involving rapid power reduction in a 500MWe Canadian Deuterium Uranium (CANDU) reactor using AutoRegressive Exogenous (ARX) algorithm. The system identification and reduced order modeling are developed from practical test data. For closed loop active control of the identified reactor model, the fractional order phase shaper along with a PID controller is shown to perform better than the present Reactor Regulating System (RRS) due to its iso-damped nature.

Synthesis of PID controllers for a class of time delay systems

In this paper we use the Hermite–Biehler theorem to establish results on the design of proportional plus integral plus derivative (PID) controllers for a class of time delay systems. Using the property of interlacing at high frequencies of the class of systems considered and linear programming we obtain the set of all stabilizing PID controllers. As far as we know, previous results on the synthesis of PID controllers rely on the solution of transcendental equations. This paper also extends previous results on the synthesis of proportional controllers for a class of delay systems of retarded type to a larger class of delay systems.

Effectiveness of Intravenous Infusion Algorithms for Glucose Control in Diabetic Patients Using Different Simulation Models

The effectiveness of closed-loop insulin infusion algorithms is assessed for three different mathematical models describing insulin and glucose dynamics within a Type I diabetes patient. Simulations are performed to assess the effectiveness of proportional plus integral plus derivative (PID) control, feedforward control, and a physiologically-based control system with respect to maintaining normal glucose levels during a meal and during exercise. Control effectiveness is assessed by comparing the simulated response to a simulation of a healthy patient during both a meal and exercise and establishing maximum and minimum glucose levels and insulin infusion levels, as well as maximum duration of hyperglycemia. Controller effectiveness is assessed within the minimal model, the Sorensen model, and the Hovorka model. Results showed that no type of control was able to maintain normal conditions when simulations were performed using the minimal model. For both the Sorensen model and the Hovorka model, proportional control was sufficient to maintain normal glucose levels. Given published clinical data showing the ineffectiveness of PID control in patients, the work demonstrates that controller success based on simulation results can be misleading, and that future work should focus on addressing the model discrepancies.

Hybrid actuator: Motion control using genetic algorithms

A hybrid actuator refers to a configuration combining the motions of two different electric motors with a mechanism to obtain a programmable output. This article presents an application of the genetic algorithm (GA) to determine optimal proportional-plus-integral-plus-derivative (PID) controller parameters to drive a seven link mechanism with an adjustable crank. A previously built model for a hybrid actuator system is used to explore the application. Simulation results are included to show how position control on both servomotors is achieved using GAs in off-line implementation.

On-Line Tension Control for Polyester Film Processing

The uniform tension at a preferred value of polyester (PET) films in processing or rewinding is important to product quality, which can be achieved by tension control. Furthermore, the uniform transport speed is helpful in creating uniform film tension. In this article, a simplified version of PET film processing systems, consisting of an unwinding roll, a sensor roller, and a rewinding roll, is considered. The unwinding roll and rewinding roll are driven by a torque-controlled motor and speed-controlled motor, respectively. A control signal to the torque-controlled motor, generated by a conventional sliding-mode controller or a fuzzy sliding-mode controller, regulates the film tension. Moreover, the speed-controlled motor adjusts the transport speed at the winding section. To improve the speed fluctuation, an external proportional-plus-integral-plus-derivative (PID) controller for the speed-controlled motor was implemented. The experimental results demonstrate that fuzzy sliding-mode control gives the tension response with smaller variation than the conventional sliding-mode control does, and the external PID control for speed diminishes fluctuations in speed, thus leading to more uniform tension, while maintaining it at the preferred value.

CCII-based PID controllers employing grounded passive components

In this paper, both of current-mode and voltage-mode proportional plus integral plus derivative (PID) controllers employing the second-generation current conveyors (CCIIs) as active elements are developed. The presented novel PID controllers have grounded passive elements that do not need passive element matching, and realize independently adjustable PID parameters. Thus, it is easy to implement these PID controllers in integrated circuits. Several computer simulations are presented to demonstrate the behavior of these proposed PID controllers.

Modeling and control of a pilot pH plant using genetic algorithm

The work described in this paper aims at exploring the use of computational intelligence (CI) techniques for designing a Wiener-model controller to perform pH control. First, genetic algorithm (GA) is utilized to identify the static inverse titration relationship of a weak-acid strong-base titration process. The resulting model of the inverse neutralization equation then serves as the component in a Wiener model controller that linearizes the pH process. As the bulk of the system non-linearity is cancelled by the inverse model, a setpoint-weighted Proportional plus Integral plus Derivative (PID) controller is used to generate the control signal. A multi-objective evolutionary algorithm (MOEA) is employed to evolve a pareto optimal set of PID parameters in order to achieve the conflicting goals of fast rise time with small overshoots. Experimental results obtained from a laboratory-scale acid–base titration process are then presented to demonstrate the feasibility of the design methodology.

Large angle attitude control of spacecraft with actuator saturation

This paper presents spacecraft large angle attitude control problem with actuator saturation limit. Traditional approach for control design for the spacecraft large angle maneuver is a fixed gain proportional plus integral plus derivative (PID) controller using quaternion attitude variables with stability guarantee. Unwanted external disturbance inputs may induce excessively large error by the PID control. Anti-windup control and intelligent integrator are effective in reducing the rapid build up of the control signal due to, in particular, integral control action. Application of the anti-windup and intelligent integrator which already have been studied extensively in other areas is made to the large angle feedback controller minimizing reaction wheel type actuator saturation. Conventional PID controller is modified by augmenting additional control actions for the purpose of performance improvement.

Relay auto-tuning of PID controllers using iterative feedback tuning

In this paper, ideas from iterative feedback tuning (IFT) are incorporated into relay auto-tuning of the proportional-plus-integral-plus-derivative (PID) controller. The PID controller is auto-tuned to give specified phase margin and bandwidth. Good tuning performance according to the specified bandwidth and phase margin can be obtained and the limitation of the standard relay auto-tuning technique using a version of Ziegler–Nichols formula can be eliminated. Furthermore, by using common modelling assumptions for the relay system, some of the required derivatives in the IFT algorithm can be derived analytically. The algorithm was tested in the laboratory on a coupled tank and good tuning result was demonstrated.

Model predictive control helps to regulate slow processes-robust barrel temperature control

Abstract Slow temperature control is a challenging control problem. The problem becomes even more challenging when multiple zones are involved, such as in barrel temperature control for extruders. Often, strict closed-loop performance requirements (such as fast startup with no overshoot and maintaining tight temperature control during production) are given for such applications. When characteristics of the system are examined, it becomes clear that a commonly used proportional plus integral plus derivative (PID) controller cannot meet such performance specifications for this kind of system. The system either will overshoot or not maintain the temperature within the specified range during the production run. In order to achieve the required performance, a control strategy that utilizes techniques such as model predictive control, autotuning, and multiple parameter PID is formulated. This control strategy proves to be very effective in achieving the desired specifications, and is very robust.

An automated neck flexibility tester.

We investigate automation and control options for the neck flexibility tester (NFT) (P. McClure et al., 1998), a device originally used to measure the flexibility of the human cervical spine. The motivation is to lay the foundations for design and implementation of investigative devices that would allow studies of mechanical properties of the spine under repetitive dynamic loading. We derive the equations of motion for an automated NFT (ANFT) using a Lagrangian formulation. These equations, which represent a simplified first-order model of the dynamics, are used to simulate the ANFT using the software package Simulink. Two control schemes are examined: proportional plus integral plus derivative (PID) control and dynamic inversion. Both are simulated for setpoint and tracking control. It appears that PID control is preferred due to its simplicity of design and relative insensitivity to the dynamic model of the ANFT.

Performance of a Thermal Nonequilibrium Plasma Jet Control System

The correlations between characteristics of a plasma jet such as gas temperature, radiation intensity, electron temperature and electron density and operating conditions such as discharge current, applied magnetic flux density, gas flow rate and rate of gas mixing with secondary gas are experimentally clarified in details. There is a linear interrelation between radiation intensity and two operating parameters of discharge current and magnetic flux density. It is shown that the radiation intensity is selected as an adjustable controlled variable, and also the discharge current and magnetic flux density are selected as manipulated variables. Then, a proportional plus integral plus derivative (PID) feedback control system is constructed utilizing the obtained physical correlations, and further the control system performance is verified. The radiation intensity can be controlled over a wide range by the discharge current in this system, and it can be also controlled with rapid and precise response when apply...

Kinematics control of a pneumatic system by hybrid fuzzy PID

In a pneumatic system, normally, the piston can stop at only two terminal endpoints. In order to extend the capabilities of the system, this research is conducted to develop a kinematics control-based pneumatic system. Both position and velocity of the pneumatic piston are controlled in such a way that the controlled piston is able to move with the specified velocity to the target position. A hybrid of fuzzy and proportional-plus-integral-plus-derivative (PID) control algorithm is proposed in this paper as the solution. The control algorithm is separated into two parts: fuzzy control and PID control. The fuzzy controller is used to control the piston when the piston locates far away from the target position whereas the PID controller is applied when the piston is near the desired position. The development starts with designing of a position sensor to detect position information of the piston. The sensor-manipulating circuit consisting of potentiometer, inverting amplifier, summing amplifier, low-pass filter and analog-to-digital converter is then designed and realized. Next, the proposed hybrid of fuzzy and PID control is implemented and programmed on the microprocessor. In order to test performance of the system, settling time and steady-state error of five control algorithms – proportional (P) control, proportional-plus-integral (PI) control, proportional-plus-derivative (PD) control, PID control, and hybrid of fuzzy and PID control – are investigated. The results from the experiments show that the proposed hybrid of fuzzy and PID control gives the most satisfied settling time and steady-state error.

Fuzzy-control of a hand orthosis for restoring tip pinch, lateral pinch, and cylindrical prehensions to patients with elbow flexion intact.

This study examines, through simulation, the use of fuzzy logic as a feasible control scheme for a hand orthosis that can restore fingertip pinch, lateral pinch, and cylindrical grasps to individuals suffering from C5-C7 spinal cord injuries. A simplified hand orthosis model, consisting of four fingers and a thumb, was derived for the purpose of planning appropriate grasp trajectories and for validating the fuzzy logic control architecture. For comparison a proportional-plus-integral-plus-derivative (PID) controller was also designed. Fuzzy logic is advantageous for this system since it eliminates solving coupled nonlinear equations of motion. For the various grips, the fuzzy controller produced better performance than the PID controller.

Feedback Control for Electromagnetic Vibration Feeder. (Applications of Two-Degrees-of-Freedom Proportional plus Integral plus Derivative Controller with Nonlinear Element).

An electromagnetic-type vibratory feeder of is a typical transportation device used in automatic weighers. As existing feeders are driven by feedforward control, the so-called “firing angle control”, the driver cannot negate sudden disturbances. In this study, we consider applying a feedback control for such a feeder system. First, we give the two details of modelings for the vibration part and for the electromagnetic force part. Next, a feedback control system is constructed for the electromagnetic vibration feeder for which we propose a two-degrees-of-freedom proportional plus integral plus derivative (PID) controller with nonlinear elements. Next, we apply the feedback control to the feeder with a standard trough. Finally, we consider a method compatible with many varieties of troughs by adjusting a nonlinear element. On the basis of the results of some experiments, we confirm that the two-degrees-of-freedom PID control is more effective than the conventional firing angle control.

A Shape Memory Alloy Actuator Using Peltier Modules and R-Phase Transition

This paper describes the development of a novel shape memory alloy (SMA) actuator with high frequency responses. By applying Peltier modules as heat pumps for heating and cooling of SMAs, the actuator is expected to have higher frequency responses comparing with conventional ones. Thermomechanical properties of the actuators; such as the deformation of SMAs and recovery forces generated during the phase transition of SMAs, were investigated first. Then, response tests of the actuators were carried out in the complete thermal cycles for cases with and without Peltier modules respectively. Based on results from numerical simulations and experiments, the transient behavior of the actuator subjected to continuous actuations has been discussed. The results show that the actuator has dramatically enhanced frequency responses. In cases where the heating and cooling are controlled by electric current sequences, the thermal instability of the actuator occurs due to the accumulation of Joule heat in Peltier modules. Therefore, a proportional plus integral plus derivative (PID) action is employed to control the temperature of the SMA, it leads to the stable actuations with the frequency responses up to 0.5 Hz.