187 research outputs found

    Fuzzy anti-windup scheme for practical control of point-to-point (Ptp) positioning systems

    Get PDF
    The Positioning Systems Generally Need A Controller To Achieve High Accuracy, Fast Response And Robustness. In Addition, Ease Of Controller Design And Simplicity Of Controller Structure Are Very Important For Practical Application. For Satisfying These Requirements, Nominal Characteristic Trajectory Following (NCTF) Controller Has Been Proposed As A Practical PTP Positioning Control. However, The Effect Of Actuator Saturation Cannot Be Completely Compensated Due To Integrator Windup Because Of Plant Parameter Variations. This Paper Presents A Method To Improve The NCTF Controller For Overcoming The Problem Of Integrator Windup By Adopting A Fuzzy Anti-Windup Scheme. The Improved NCTF Controller Is Evaluated Through Simulation Using Dynamic Model Of A Rotary Positioning System. The Results Show That The Improved NCTF Controller Is Adequate To Compensate The Effect Of Integrator Windup

    Fuzzy antiwindup schemes for NCTF control of Point-Topoint (PTP) positioning systems

    Get PDF
    The positioning systems generally need a controller to achieve high accuracy, fast response and robustness. In addition, ease of controller design and simplicity of controller structure are very important for practical application. For satisfying these requirements, NCTF (nominal characteristic trajectory following) controller has been proposed as a practical PTP positioning control. However, the effect of actuator saturation can not be completely compensated due to integrator windup because of plant parameter variations. This study presents a method to improve the NCTF controller for overcoming the problem of integrator windup by adopting fuzzy anti-windup schemes. Two fuzzy antiwindup schemes based on Mamdani and Takagi-Sugeno fuzzy system are developed and evaluated their effectiveness. The improved NCTF controller with the proposed fuzzy anti-windup schemes is evaluated through simulation using dynamic model of a rotary positioning system. The results show that the improved NCTF controller with Takagi-Sugeno-based fuzzy windup is the best scheme to compensate for the effect of integrator windup

    Practical Control for Two-Mass Positioning Systems in Presence of Saturation

    Get PDF
     The precision positioning systems generally need a good controller to achieve a fast response, high accuracy and robustness. In addition, ease, simplicity of controller design structure and high motion control performance are very important for practical applications. For satisfying these requirements, nominal characteristic trajectory (NCT) with proportional integral (PI) and notch filter (NF) as a compensator has been proposed as a practical control method for two-mass rotary PTP positioning systems. However, the effect of the actuator saturation cannot be completely compensated due to integrator windup when the object parameter varies. This paper presents a method to further improve nominal characteristic trajectory following (NCTF) controller to overcome the problem of integrator windup by adopting PI anti-windup schemes. The improved NCTF controller is evaluated experimentally using two-mass rotary positioning systems. The effect of the design parameters on the robustness of the improved NCTF with anti-windup integrator controller is evaluated and compared with NCTF without anti-windup integrator and the equivalent PID controller. The results show that the improved NCTF controller is effective to compensate the effect of integrator windup

    Control strategy for automatic gantry crane systems: a practical and intelligent approach

    Get PDF
    The use of gantry crane systems for transporting payload is very common in building constructions. However, moving the payload using the crane is not an easy task especially when strict specifications on the swing angle and on the transfer time need to be satisfied. Various attempts in controlling gantry cranes system based on open- loop and closed-loop control systems were proposed. However, most of the proposed controllers were designed based on the model and parameter of the crane system. In general, modeling and parameter identifications are troublesome and time consuming task. To overcome this problem, in this paper, a practical and intelligent control method for automatic gantry crane is introduced and evaluated experimentally. The results show that the proposed method is not only effective for controlling the crane but also robust to parameter variation

    Artificial intelligent based friction modelling and compensation in motion control system

    Get PDF
    The interest in the study of friction in control engineering has been driven by the need for 10 precise motion control in most of industrial applications such as machine tools, robot 11 systems, semiconductor manufacturing systems and Mechatronics systems. Friction has 12 been experimentally shown to be a major factor in performance degradation in various 13 control tasks. Among the prominent effects of friction in motion control are: steady state 14 error to a reference command, slow response, periodic process of sticking and sliding (stick-15 slip) motion, as well as periodic oscillations about a reference point known as hunting when 16 an integral control is employed in the control scheme. Table 1 shows the effects and type of 17 friction as highlighted by Armstrong et. al.(1994). It is observed that, each of task is 18 dominated by at least one friction effect ranging from stiction, or/and kinetic to negative 19 friction (Stribeck). Hence, the need for accurate compensation of friction has become 20 important in high precision motion control. Several techniques to alleviate the effects of 21 friction have been reported in the literature (Dupont and Armstrong, 1993; Wahyudi, 2003; 22 Tjahjowidodo, 2004; Canudas, et. al., 1986). 23 One of the successful methods is the well-known model-based friction compensation 24 (Armstrong et al., 1994; Canudas de Wit et al., 1995 and Wen-Fang, 2007). In this method, 25 the effect of the friction is cancelled by applying additional control signal which generates a 26 torque/force. The generated torque/force has the same value (or approximately the same) 27 with the friction torque/force but in opposite direction

    Design And Analysis On The Robust Control Of A X-Y Ballscrew Mechanism

    Get PDF
    This thesis presents the design and analysis on the robust control of a X-Y ballscrew mechanism. In this research, a practical and robust controller for positioning control is discussed. The Continuous Motion Nominal Characteristic Trajectory Following (CM NCTF) controller is investigated in this research for tracking motion of an AC driven X-Y ballscrew mechanism. The CM NCTF controller has a simple control structure and straightforward design procedure that does not require an exact model parameter of a plant. In order to enhance the accuracy of the control system, a suitable input signal is designed to make sure the X-Y ballscrew mechanism attenuate smoothly in the deceleration motion. The CM NCTF controller consists of a Nominal Characteristic Trajectory (NCT) and a Proportional and Integral (PI) compensator. The NCT is constructed using the open-loop experimental responses while the PI compensator is designed based on a practical stability limit obtained experimentally. The CM NCTF controller has been evaluated in tracking motion performance. In order to examine the adaptability of the controller to the change of the input, experiments with various inputs is carried out. Besides that, the robustness of the controller is validated through the change of the load of the system. In order to examine the usefulness of the CM NCTF controller, a PI-D controller that has a similar control structure is designed and compared. The tracking performance of the CM NCTF controller is evaluated in maximum peak error Emax, percentage of error Epercent, and root mean square of error Erms. Emax is the difference between the output peak and the reference input, and Epercent is the percentage of the peak error with respect to the reference input. The experimental results proved that the CM NCTF controller has demonstrated better positioning response than the conventional NCTF controller and the PI-D controller by showing a two times smaller motion error. The robustness of the CM NCTF controller is clarified using X-axis, which has heavier load than the Y-axis. The experimental results have again proved that the CM NCTF controller demonstrates better tracking performance than the conventional NCTF controller and the PI-D controller in X-axis. As a conclusion, the CM NCTF controller has better positioning performance as compared to the conventional NCTF controller and PI-D controller. In future, the contour motion for X-axis and Y-axis will be done to evaluate accuracy of the controller. Besides that, the robustness performance in term of change of disturbance force will be considered

    Nonlinear, Adaptive and Fault-tolerant Control for Electro-hydraulic Servo Systems

    Get PDF

    Practical Controller Design For Ultra-Precision Positioning Of Stages With A Pneumatic Artificial Muscle Actuator

    Get PDF
    This paper presents a practical controller design method for ultraprecision positioning of pneumatic artificial muscle actuator stages. Pneumatic artificial muscle (PAM) actuators are safe to use and have numerous advantages which have brought these actuators to wide applications. However, PAM exhibits strong non-linear characteristics, and these limitations lead to low controllability and limit its application. In practice, the non-linear characteristics of PAM mechanism are difficult to be precisely modeled, and time consuming to model them accurately. The purpose of the present study is to clarify a practical controller design method that emphasizes a simple design procedure that does not acquire plants parameters modeling, and yet is able to demonstrate ultraprecision positioning performance for a PAM driven stage. The practical control approach adopts continuous motion nominal characteristic trajectory following (CM NCTF) control as the feedback controller. The constructed PAM driven stage is in low damping characteristic and causes severe residual vibration that deteriorates motion accuracy of the system. Therefore, the idea to increase the damping characteristic by having an acceleration feedback compensation to the plant has been proposed. The effectiveness of the proposed controller was verified experimentally and compared with a classical PI controller in point-topoint motion. The experiment results proved that the CM NCTF controller demonstrates better positioning performance in smaller motion error than the PI controller. Overall, the CM NCTF controller has successfully to reduce motion error to 3µm, which is 88.7% smaller than the PI controlle

    Advances in PID Control

    Get PDF
    Since the foundation and up to the current state-of-the-art in control engineering, the problems of PID control steadily attract great attention of numerous researchers and remain inexhaustible source of new ideas for process of control system design and industrial applications. PID control effectiveness is usually caused by the nature of dynamical processes, conditioned that the majority of the industrial dynamical processes are well described by simple dynamic model of the first or second order. The efficacy of PID controllers vastly falls in case of complicated dynamics, nonlinearities, and varying parameters of the plant. This gives a pulse to further researches in the field of PID control. Consequently, the problems of advanced PID control system design methodologies, rules of adaptive PID control, self-tuning procedures, and particularly robustness and transient performance for nonlinear systems, still remain as the areas of the lively interests for many scientists and researchers at the present time. The recent research results presented in this book provide new ideas for improved performance of PID control applications
    corecore