Wyniki wyszukiwania - Biblioteka Nauki

1

Control and path prediction of an Automate Guided Vehicle

100%

Butdee S. , Suebomran A. , Vignat F. , Yarlagadda P. K.

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2008

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tom Vol. 31, nr 2

442-448

EN

Purpose: In this paper a new architecture and control strategy of an AGV is proposed. It is organized as follows. The system architecture is explained in section 2. Section 3 deals with the kinematics model of the AGV path, prediction and control. Section 4 describes the experiments. The conclusion and recommendation are given in section 5. Design/methodology/approach: It is a three wheels vehicle. The front wheel is used for driving and steering the AGV and the two rear wheels are free. The steering and driving are DC motor. Two encoders are individually attached on the two rear wheels in order to measure the vehicle displacement and then calculate its real timeposition and orientation. The choice of positioning the encoders on the free wheels provides to the vehicle anaccurate measurement of its progression. A programmable logic control (PLC) is used for motion control. Findings: In this paper, An Automate Guided Vehicle (AGV) is presented. The developed algorithm is based on memorised path and kinematics determination of the movement. The vehicle position and deviation are calculated from rear wheels rotation measurement. The steering and driving command are determined from this deviation. Localization of AGV by Kaman filtering algorithm is presented. Control of AGV motion is implemented by using PID control scheme. Displacement axis and steering axis are separated to implement the motion control. We proposed the localization system for estimation of AGV. Position and orientation are estimated by Kalman filtering in state-space model. Position and orientation of AGV are measured and used for simulation for localization system. We conclude that the vehicle can reach from the initial position moved along with generated path with accurate location. A Schneider PLC is used to implement this control. The tests reveal a smooth movement and convenient deviation. Practical implications: The first prototype working, the next research steps will be development of a correction system to correct none detected errors. It will also be necessary to develop the fleet management strategy and software. Originality/value: Future work is planed to increase the accuracy of the system by equip more sensors for observation technique. Treatment of dynamic model and machine vision application of automated vehicle are also planed to the next step.

2

Analysis of nonlinear model following control/internal model control (MFC/IMC) structure for a ship engine speed control

80%

Brzózka J.

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2008

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tom Vol. 34, no 3

25-29

EN

Ship governors are usually designed on the basis of PID (Proportional Integral Derivative) controllers because of their simplicity, reliability and universality. However, their performance in various environmental conditions is not as good as desired. These disadvantages can be overcome by adaptive controllers, although these methods are complex. This article presents a new control loop structure for a ship engine speed control based on the model following control (MFC) and internal model control (IMC) theory. The new structure presented has the advantages of both the PID and robust control methodologies. It is robust for large parameter variations and strong environmental disturbances. Simulations using MATLAB®/Simulink® software for a real ship engine parameters showed high effectiveness of MFC/IMC structure for speed-keeping and speed-changing.

3

Tuning fractional PID controllers for a Steward platform based on frequency domain and artificial intelligence methods

70%

Copot C. , Zhong Y. , Ionescu C. , Keyser R.

Open Physics

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2013

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tom 11

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nr 6

702-713

EN

In this paper, two methods to tune a fractional-order PI λ D μ controller for a mechatronic system are presented. The first method is based on a genetic algorithm to obtain the parameter values for the fractionalorder PI λ D μ controller by global optimization. The second method used to design the fractional-order PI λ D μ controller relies on an auto-tuning approach by meeting some specifications in the frequency domain. The real-time experiments are conducted using a Steward platform which consists of a table tilted by six servo-motors with a ball on the top of the table. The considered system is a 6 degrees of freedom (d.o.f.) motion platform. The feedback on the position of the ball is obtained from images acquired by a visual sensor mounted above the platform. The fractional-order controllers were implemented and the performances of the steward platform are analyzed.

4

Control error dynamic modification as an efficient tool for reduction of effects introduced by actuator constraints

60%

Janiszowski K.

International Journal of Applied Mathematics and Computer Science

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2009

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tom 19

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nr 2

271-279

EN

A modification of digital controller algorithms, based on the introduction of a virtual reference value, which never exceeds active constraints in the actuator output is presented and investigated for some algorithms used in single-loop control systems. This idea, derived from virtual modification of a control error, can be used in digital control systems subjected to both magnitude and rate constraints. The modification is introduced in the form of on-line adaptation to the control task. Hence the design of optimal (in a specified sense) digital controller parameters can be separated from actuator constraints. The adaptation of the control algorithm (to actuator constraints) is performed by the transformation of the control error and is equivalent to the introduction of a new, virtual reference value for the control system. An application of this approach is presented through examples of three digital control algorithms: the PID algorithm, the dead-beat controller and the state space controller. In all cases, clear advantages of transients are observed, which yields some general conclusions to the problem of processing actuator constraints in control.

5

Neural network parallel force/position control of robot manipulators under environment and robot dynamics uncertainties

60%

Ferguene F. , Achour N. , Toumi R.

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2009

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tom Vol. 19, no. 1

93-121

EN

The performance of a parallel force/position controller for robot force tracking is affected by the uncertainties in both the robot dynamics and the environment stiffness. This paper aims to improve the controller's robustness by applying the neural network (NN) technique to compensate for the robot dynamics at the input trajectory level and adaptive feed-forward compensation to cope with variations in the contact environment. A NN control technique is applied to a conventional PID force/position parallel control scheme which is composed of a PD action on position loop and a proposed adaptive I (integral) action on the force loop, which allows a complete use of available sensor measurements by operating the control action in a full dimensional space without using selection matrices. Simulation results for a three degrees-of-freedom robot show that highly robust position/force tracking can be achieved in the presence of a full dynamic robot and large environment stiffness uncertainties.

6

Neural network based feedback linearization control of a servo-hydraulic vehicle suspension system

60%

Pedro J. , Dahunsi O.

International Journal of Applied Mathematics and Computer Science

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2011

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tom 21

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nr 1

137-147

EN

This paper presents the design of a neural network based feedback linearization (NNFBL) controller for a two degree-offreedom (DOF), quarter-car, servo-hydraulic vehicle suspension system. The main objective of the direct adaptive NNFBL controller is to improve the system's ride comfort and handling quality. A feedforward, multi-layer perceptron (MLP) neural network (NN) model that is well suited for control by discrete input-output linearization (NNIOL) is developed using input-output data sets obtained from mathematical model simulation. The NN model is trained using the Levenberg-Marquardt optimization algorithm. The proposed controller is compared with a constant-gain PID controller (based on the Ziegler-Nichols tuning method) during suspension travel setpoint tracking in the presence of deterministic road disturbance. Simulation results demonstrate the superior performance of the proposed direct adaptive NNFBL controller over the generic PID controller in rejecting the deterministic road disturbance. This superior performance is achieved at a much lower control cost within the stipulated constraints.

7

Voltage/current control mode for combined three-phase inverter

51%

Wang H. , Yue X. , Pei X. , Kang Y.

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2010

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tom R. 86, nr 11a

358-362

EN

For parallel inverters system, controlling the output voltage in normal operation constantly is named the voltage control mode (VCM), and controlling the output current constantly in abnormal operation conditions (such as short circuit) is named the current control mode (CCM). The combined three-phase inverter topology is presented, the equivalent inverter topology with a LCL filter is obtained and mathematical models are built in VCM and CCM. A hybrid control strategy is proposed. The PID control and the repetitive control are used in VCM to obtain the fast dynamic responses and low harmonic distortions. On the other hand, the state feedback control is used in CCM. Pole assignment has been employed in designing parameter of the PID controller and state feedback, and the repetitive control design process is given. Experimental results validate the proposed control using two 400KVA parallel inverters.

PL

Dla równoległego systemu przekształtników zazwyczaj stosuje się system kontroli napięcia VCM i system kontroli prądu CCM (w warunkach specjalnych - np. zwarcia). Zaprezentowano topologie przekształtnika trójfazowego. Odpowiednia topologia przekształtnika z filtrem LCL została przedstawiona. Zaproponowano hybrydową strategię sterowania. System PID sterowania użyty w VCM zapewnia szybką odpowiedź dynamiczną i małe zniekształcenia. W układzie CCM użyto stałego sprzężenia zwrotnego. Sprawdzono położenie biegunów. Wyniki eksperymentu z dwoma 400kVA równoległymi przekształtnikami potwierdziły założenia.

8

Phase Locked Loop for Distorted Three-Phase Systems tested with a PI, a PID and a Fractional PI

41%

Minambres V. , Milanés M. , Vinagre B. , Romero E.

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2009

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tom R. 85, nr 10

201-207

EN

This paper proposes a Phase Locked Loop algorithm for three-phase distorted systems. For the Phase Locked Loop it is deduced a mathematical model to design the three different control solutions implemented: a PI, a PID and a novel fractional PI. The damping ratio, the time response and the phase error of the phase tracking system are the criteria to design the controllers. The performance of the three systems is analyzed by connecting inputs with imbalance, harmonics and phase and/or frequency variations. An Autoadjustable Synchronous Reference Frame application is developed to test the Phase Locked Loop by simulation and experimentally through xPCTarget. A comparison of some parameters of the system such as phase margin, settling time, THD and phase error is carried out for each controller.

PL

W artykule zaproponowano algorytm pętli synchronizacji fazy dla odkształconych przebiegów w systemach trójfazowych. Sformułowano model matematyczny pętli fazowej służący opracowaniu rozwiązań z regulatorami PI, PID oraz nowatorskim, ułamkowym PI. Kryteriami projektowymi są poziom tłumienia, czas odpowiedzi i błąd fazowy układu śledzenia. Właściwości trzech systemów zostały zbadane przy zastosowaniu sygnałów niesymetrycznych, odkształconych oraz z wahaniami fazy i częstotliwości. Pętle fazowe testowane były symulacyjnie i doświadczalnie poprzez xPCTarget przy użyciu aplikacji Autoadjustable Synchronous Reference Frame. Przedstawiono porównanie wybranych parametrów takich jak marines fazy, czas synchronizacji, THD i błąd fazowy.