The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Bijan Shirinzadeh - One of the best experts on this subject based on the ideXlab platform.

  • design and Control Methodology of a 3 dof flexure based mechanism for micro nano positioning
    Robotics and Computer-integrated Manufacturing, 2015
    Co-Authors: Z Guo, Bijan Shirinzadeh, Yanling Tian, C Liu, Fujun Wang, Xianping Liu, Dawei Zhang
    Abstract:

    A 3-DOF (X-Y-?Z) planar flexure-based mechanism is designed and monolithically manufactured using Wire Electro-Discharge Machining (WEDM) technology. The compact flexure-based mechanism is directly driven by three piezoelectric actuators (PZTs) through decoupling mechanisms. The orthogonal configuration in the x and y directions can guarantee the decoupling translational motion in these axes. The rotational motion and translational displacement in the x direction can be decoupled by Controlling the piezoelectric actuators in the x axis with the same displacement values in same and opposite motion directions, respectively. The static and dynamic models of the developed flexure-based mechanism have been developed based on the pseudo-rigid-body model Methodology. The mechanical design optimization is conducted to improve the static and dynamic characteristics of the flexure-based mechanism. Finite Element Analyses (FEA) are also carried out to verify the established models and optimization results. A novel hybrid feedforward/feedback Controller has been provided to eliminate/reduce the nonlinear hysteresis and external disturbance of the flexure-based mechanism. Experimental testing has been performed to examine the dynamic performance of the developed flexure-based mechanism. The mechanical design Methodology for a compact 3-DOF planar flexure-based mechanism has been developed.Influences of the Hertzian contact stiffness on the dynamic performance of the developed mechanism have been explored.A novel hybrid feedforward/feedback Controller has been proposed to reduce/eliminate the hysteresis.

  • robust adaptive constrained motion tracking Control of piezo actuated flexure based mechanisms for micro nano manipulation
    IEEE Transactions on Industrial Electronics, 2011
    Co-Authors: Hwee Choo Liaw, Bijan Shirinzadeh
    Abstract:

    This paper presents a robust adaptive constrained motion tracking Control Methodology for piezo-actuated flexure-based micro/nano manipulation mechanisms. This unique Control approach is established for the tracking of desired motion trajectories in a constrained environment exhibiting some degree of uncertain stiffness. The Control Methodology is also formulated to accommodate not only the parametric uncertainties and unknown force conversion function, but also nonlinearities including the hysteresis effect and external disturbances in the motion systems. In this paper, the equations for the dynamic modeling of a flexure-hinged four-bar micro/nano manipulation mechanism operating in a constrained environment are established. A lumped parameter dynamic model that combines the piezoelectric actuator and the micro/nano manipulation mechanism is developed for the formulation of the Control Methodology. Stability analysis of the proposed closed-loop system is conducted and the convergence of the motion tracking errors is proven theoretically. Furthermore, precise motion tracking ability in following a desired motion trajectory is demonstrated in the experimental study. An important advantage of this Control approach is that it does not require the exact values for the system parameters and the force conversion function in the physical realization. This proposed constrained motion tracking Control Methodology is very useful for applications demanding high-precision motion tracking with force sensing and feedback.

  • a flexure based mechanism and Control Methodology for ultra precision turning operation
    Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology, 2009
    Co-Authors: Bijan Shirinzadeh, Yanling Tian, Dawei Zhang
    Abstract:

    This paper presents the Methodology for modeling and Control of a high precision flexure-based mechanism for ultra-precision turning operation. A high performance piezoelectric actuator is used to driven the flexure-based mechanism. A parallel flexure hinge mechanism is utilized to guide the moving platform and to preload the piezoelectric actuator. A high resolution capacitive sensor is used to measure the displacement of the flexure-based mechanism for closed-loop Control. With consideration of the driving circuit, the dynamic model of the flexure-based mechanism has been established. The effect of the driving circuit on the dynamic response of the precision mechanism is investigated. Experimental tests have been carried out to verify the established model and the performance of the flexure-based mechanism.

  • robust neural network motion tracking Control of piezoelectric actuation systems for micro nanomanipulation
    IEEE Transactions on Neural Networks, 2009
    Co-Authors: Hwee Choo Liaw, Bijan Shirinzadeh, Julian A Smith
    Abstract:

    This paper presents a robust neural network motion tracking Control Methodology for piezoelectric actuation systems employed in micro/nanomanipulation. This Control Methodology is proposed for tracking of desired motion trajectories in the presence of unknown system parameters, nonlinearities including the hysteresis effect and external disturbances in the Control systems. In this paper, the related Control issues are investigated, and a Control Methodology is established including the neural networks and a sliding Control scheme. In particular, the radial basis function (RBF) neural networks are chosen for function approximations. The stability of the closed-loop system, as well as the convergence of the position and velocity tracking errors to zero, is assured by the Control Methodology in the presence of the aforementioned conditions. An offline learning procedure is also proposed for the improvement of the motion tracking performance. Precise tracking results of the proposed Control Methodology for a desired motion trajectory are demonstrated in the experimental study. With such a motion tracking capability, the proposed Control Methodology promises the realization of high-performance piezoelectric actuated micro/nanomanipulation systems.

  • robust generalised impedance Control of piezo actuated flexure based four bar mechanisms for micro nano manipulation
    Sensors and Actuators A-physical, 2008
    Co-Authors: Hwee Choo Liaw, Bijan Shirinzadeh
    Abstract:

    This paper presents a novel robust generalised impedance Control Methodology for piezo-actuated flexure-based four-bar micro/nano manipulation mechanisms. This Control approach is proposed for compliant manipulation in which desired motion and force trajectories are Controlled to achieve a specified generalised impedance. The Control Methodology is also formulated to accommodate not only the parametric uncertainties and unknown force conversion function, but also non-linearities including the hysteresis effect and external disturbances in the motion systems. In this paper, the equations for dynamic modelling of a flexure-hinged four-bar micro/nano mechanism making contact with its environment are established. A lumped parameter dynamic model that combines the piezoelectric actuator and the micro/nano mechanism is established for the formulation of the proposed Control Methodology. The stability of the Control approach is analysed, and the convergence of the tracking errors to achieve the generalised impedance is proven theoretically. Desirable Control performances in following the desired motion and force trajectories are demonstrated in the experimental study. An important advantage of this Control Methodology is that this approach does not require the exact values for the system parameters and the force conversion function in the physical realisation. This proposed compliant manipulation Control Methodology is useful for the implementation of high performance flexure-based micro/nano manipulation applications demanding for both sensing and Control of motion and force trajectories.

Hwee Choo Liaw - One of the best experts on this subject based on the ideXlab platform.

  • sliding mode disturbance observer based motion Control for a piezoelectric actuator based surgical device
    Asian Journal of Control, 2018
    Co-Authors: Wenyu Liang, Hwee Choo Liaw
    Abstract:

    This paper presents a sliding mode disturbance observer-based motion tracking Control Methodology. In particular, the Methodology is applied to Control a semi-automated hand-held ear surgical device for the treatment of otitis media with effusion. The proposed Control Methodology is utilised to deal with the undesirable effects in the motion system, such as non-linear dynamics, parametric uncertainties and external disturbances. It employs a proportional-derivative Control scheme together with a sliding mode disturbance observer for rejecting the undesirable effects. The stability of the proposed Control Methodology is proven theoretically and its effectiveness is evaluated experimentally. In addition, promising motion tracking experimental results are shown, and it can be observed that the proposed approach offers more robust performance for Controlling the hand-held surgical device and other similar instruments.

  • robust adaptive constrained motion tracking Control of piezo actuated flexure based mechanisms for micro nano manipulation
    IEEE Transactions on Industrial Electronics, 2011
    Co-Authors: Hwee Choo Liaw, Bijan Shirinzadeh
    Abstract:

    This paper presents a robust adaptive constrained motion tracking Control Methodology for piezo-actuated flexure-based micro/nano manipulation mechanisms. This unique Control approach is established for the tracking of desired motion trajectories in a constrained environment exhibiting some degree of uncertain stiffness. The Control Methodology is also formulated to accommodate not only the parametric uncertainties and unknown force conversion function, but also nonlinearities including the hysteresis effect and external disturbances in the motion systems. In this paper, the equations for the dynamic modeling of a flexure-hinged four-bar micro/nano manipulation mechanism operating in a constrained environment are established. A lumped parameter dynamic model that combines the piezoelectric actuator and the micro/nano manipulation mechanism is developed for the formulation of the Control Methodology. Stability analysis of the proposed closed-loop system is conducted and the convergence of the motion tracking errors is proven theoretically. Furthermore, precise motion tracking ability in following a desired motion trajectory is demonstrated in the experimental study. An important advantage of this Control approach is that it does not require the exact values for the system parameters and the force conversion function in the physical realization. This proposed constrained motion tracking Control Methodology is very useful for applications demanding high-precision motion tracking with force sensing and feedback.

  • robust neural network motion tracking Control of piezoelectric actuation systems for micro nanomanipulation
    IEEE Transactions on Neural Networks, 2009
    Co-Authors: Hwee Choo Liaw, Bijan Shirinzadeh, Julian A Smith
    Abstract:

    This paper presents a robust neural network motion tracking Control Methodology for piezoelectric actuation systems employed in micro/nanomanipulation. This Control Methodology is proposed for tracking of desired motion trajectories in the presence of unknown system parameters, nonlinearities including the hysteresis effect and external disturbances in the Control systems. In this paper, the related Control issues are investigated, and a Control Methodology is established including the neural networks and a sliding Control scheme. In particular, the radial basis function (RBF) neural networks are chosen for function approximations. The stability of the closed-loop system, as well as the convergence of the position and velocity tracking errors to zero, is assured by the Control Methodology in the presence of the aforementioned conditions. An offline learning procedure is also proposed for the improvement of the motion tracking performance. Precise tracking results of the proposed Control Methodology for a desired motion trajectory are demonstrated in the experimental study. With such a motion tracking capability, the proposed Control Methodology promises the realization of high-performance piezoelectric actuated micro/nanomanipulation systems.

  • robust generalised impedance Control of piezo actuated flexure based four bar mechanisms for micro nano manipulation
    Sensors and Actuators A-physical, 2008
    Co-Authors: Hwee Choo Liaw, Bijan Shirinzadeh
    Abstract:

    This paper presents a novel robust generalised impedance Control Methodology for piezo-actuated flexure-based four-bar micro/nano manipulation mechanisms. This Control approach is proposed for compliant manipulation in which desired motion and force trajectories are Controlled to achieve a specified generalised impedance. The Control Methodology is also formulated to accommodate not only the parametric uncertainties and unknown force conversion function, but also non-linearities including the hysteresis effect and external disturbances in the motion systems. In this paper, the equations for dynamic modelling of a flexure-hinged four-bar micro/nano mechanism making contact with its environment are established. A lumped parameter dynamic model that combines the piezoelectric actuator and the micro/nano mechanism is established for the formulation of the proposed Control Methodology. The stability of the Control approach is analysed, and the convergence of the tracking errors to achieve the generalised impedance is proven theoretically. Desirable Control performances in following the desired motion and force trajectories are demonstrated in the experimental study. An important advantage of this Control Methodology is that this approach does not require the exact values for the system parameters and the force conversion function in the physical realisation. This proposed compliant manipulation Control Methodology is useful for the implementation of high performance flexure-based micro/nano manipulation applications demanding for both sensing and Control of motion and force trajectories.

  • sliding mode enhanced adaptive motion tracking Control of piezoelectric actuation systems for micro nano manipulation
    IEEE Transactions on Control Systems and Technology, 2008
    Co-Authors: Hwee Choo Liaw, Bijan Shirinzadeh, Julian A Smith
    Abstract:

    This paper proposes a sliding-mode enhanced adaptive Control Methodology for piezoelectric actuation systems to track specified motion trajectories. This Control Methodology is proposed to overcome the problems of unknown or uncertain system parameters, nonlinearities including the hysteresis effect, and external disturbances in the piezoelectric actuation systems, without any form of feedforward compensation. In this paper, a special class of positive definite functions is employed to formulate the Control Methodology such that the closed-loop system stability can be guaranteed. The Control formulation, stability analysis, and analytical closed-loop solution are presented. Furthermore, a precise tracking ability in following a specified motion trajectory is demonstrated in the experimental study. With the capability of motion tracking under the aforementioned conditions, the sliding-mode enhanced adaptive Control Methodology is very attractive in realising high-performance Control applications in the field of micro/nano manipulation.

Julian A Smith - One of the best experts on this subject based on the ideXlab platform.

  • robust neural network motion tracking Control of piezoelectric actuation systems for micro nanomanipulation
    IEEE Transactions on Neural Networks, 2009
    Co-Authors: Hwee Choo Liaw, Bijan Shirinzadeh, Julian A Smith
    Abstract:

    This paper presents a robust neural network motion tracking Control Methodology for piezoelectric actuation systems employed in micro/nanomanipulation. This Control Methodology is proposed for tracking of desired motion trajectories in the presence of unknown system parameters, nonlinearities including the hysteresis effect and external disturbances in the Control systems. In this paper, the related Control issues are investigated, and a Control Methodology is established including the neural networks and a sliding Control scheme. In particular, the radial basis function (RBF) neural networks are chosen for function approximations. The stability of the closed-loop system, as well as the convergence of the position and velocity tracking errors to zero, is assured by the Control Methodology in the presence of the aforementioned conditions. An offline learning procedure is also proposed for the improvement of the motion tracking performance. Precise tracking results of the proposed Control Methodology for a desired motion trajectory are demonstrated in the experimental study. With such a motion tracking capability, the proposed Control Methodology promises the realization of high-performance piezoelectric actuated micro/nanomanipulation systems.

  • sliding mode enhanced adaptive motion tracking Control of piezoelectric actuation systems for micro nano manipulation
    IEEE Transactions on Control Systems and Technology, 2008
    Co-Authors: Hwee Choo Liaw, Bijan Shirinzadeh, Julian A Smith
    Abstract:

    This paper proposes a sliding-mode enhanced adaptive Control Methodology for piezoelectric actuation systems to track specified motion trajectories. This Control Methodology is proposed to overcome the problems of unknown or uncertain system parameters, nonlinearities including the hysteresis effect, and external disturbances in the piezoelectric actuation systems, without any form of feedforward compensation. In this paper, a special class of positive definite functions is employed to formulate the Control Methodology such that the closed-loop system stability can be guaranteed. The Control formulation, stability analysis, and analytical closed-loop solution are presented. Furthermore, a precise tracking ability in following a specified motion trajectory is demonstrated in the experimental study. With the capability of motion tracking under the aforementioned conditions, the sliding-mode enhanced adaptive Control Methodology is very attractive in realising high-performance Control applications in the field of micro/nano manipulation.

  • robust motion tracking Control of piezo driven flexure based four bar mechanism for micro nano manipulation
    Mechatronics, 2008
    Co-Authors: Hwee Choo Liaw, Bijan Shirinzadeh, Julian A Smith
    Abstract:

    Abstract This paper presents a robust motion tracking Control Methodology for a flexure-based four-bar micro/nano manipulator driven by a piezoelectric actuator. This Control Methodology is proposed for tracking desired motion trajectories in view of the problems of unknown or uncertain system parameters, non-linearities including the hysteresis effect, and external disturbances in the system. In this paper, equations of the angular stiffness, ‘static’ linear stiffness, and structural resonance of a flexure-hinged mechanism are presented. In addition, a lumped parameter dynamic model is established for the formulation of the proposed Control Methodology. The convergence of the position tracking error to zero is assured by the approach in the presence of the aforementioned conditions. The stability of the closed-loop system is proven theoretically, and a precise tracking performance in following a desired motion trajectory is demonstrated in the experimental study. One of the most important advantages of this Control Methodology is that the approach requires only a knowledge of the estimated lumped parameters in the physical realisation. With the capability of motion tracking, the robust motion Control Methodology is very attractive in realising high-performance flexure-based Control applications in the field of micro/nano manipulation.

  • enhanced sliding mode motion tracking Control of piezoelectric actuators
    Sensors and Actuators A-physical, 2007
    Co-Authors: Hwee Choo Liaw, Bijan Shirinzadeh, Julian A Smith
    Abstract:

    This paper proposes an enhanced sliding mode motion tracking Control Methodology for piezoelectric actuators to track desired motion trajectories. The proposed Control Methodology is established to accommodate parametric uncertainties, nonlinearities including the hysteresis effect, and other un-modelled disturbances, without any form of feed-forward compensation. The fundamental concept in this Control strategy relies on the specification of a target performance and the formulation of an enhanced sliding mode Control law based on the variable structure Control approach. The Control Methodology ensures the convergence of the position tracking error to zero in the presence of the aforementioned conditions. The stability of the Control Methodology is proven theoretically and a precise tracking ability is demonstrated in the experimental study. One of the most important advantages of this Control Methodology is that the approach requires only a knowledge of the estimated system parameters together with their corresponding bounds and the bound of the non-linearities and disturbances in the physical realisation. Being capable of motion tracking, the proposed enhanced sliding mode Control Methodology is very attractive in the field of micro/nano manipulation through which high-precision piezoelectric actuation Control applications can be realised.

Naira Hovakimyan - One of the best experts on this subject based on the ideXlab platform.

  • l 1 adaptive Controller for nonlinear systems in the presence of unmodelled dynamics part ii
    American Control Conference, 2008
    Co-Authors: Chengyu Cao, Naira Hovakimyan
    Abstract:

    This paper presents a novel adaptive Control Methodology for a class of uncertain nonlinear systems in the presence of unmodelled dynamics. The adaptive Controller ensures uniformly bounded transient response for system's both input and output signals simultaneously. The performance bounds can be systematically improved by increasing the adaptation gain.

  • cal l _1 adaptive output feedback Controller for systems of unknown dimension
    IEEE Transactions on Automatic Control, 2008
    Co-Authors: Chengyu Cao, Naira Hovakimyan
    Abstract:

    This note presents novel adaptive output feedback Control Methodology for systems of unknown dimension in the presence of unmodeled dynamics and time-varying uncertainties. The adaptive output feedback Controller ensures uniformly bounded transient and asymptotic tracking for the system's both signals, input and output, simultaneously. The performance bounds can be systematically improved by increasing the adaptation rate. Simulations of an unstable nonminimum phase system verify the theoretical findings.

  • novel l1 adaptive Control Methodology for aerial refueling with guaranteed transient performance
    Journal of Guidance Control and Dynamics, 2008
    Co-Authors: Jiang Wang, Chengyu Cao, Naira Hovakimyan, Vijay V Patel, Eugene Lavretsky
    Abstract:

    Autonomous aerial refueling autopilot design is addressed in this paper using a novel C 1 neural-network-based adaptive Control approach, which is capable of accommodating trailing-vortex-induced uncertainties and uncertainties in Control effectiveness. The main advantage of the new approach is its ability of fast adaptation that leads to uniform transient performance for the system's signals, both inputs and outputs, simultaneously, with guaranteed performance specifications. Simulation results verify the benefit of this new approach.

  • guaranteed transient performance with l1 adaptive Controller for systems with unknown time varying parameters and bounded disturbances part i
    American Control Conference, 2007
    Co-Authors: Chengyu Cao, Naira Hovakimyan
    Abstract:

    This paper presents a novel adaptive Control Methodology for uncertain systems with time-varying unknown parameters and time-varying bounded disturbances. The adaptive Controller ensures uniformly bounded transient and asymptotic tracking for system's both signals, input and output, simultaneously. The performance bounds can be systematically improved by increasing the adaptation rate. Simulations of a robotic arm with time-varying friction verify the theoretical findings.

  • adaptive output feedback Control Methodology applicable to non minimum phase nonlinear systems
    Automatica, 2006
    Co-Authors: Naira Hovakimyan, Bongjun Yang, Anthony J Calise
    Abstract:

    An adaptive output feedback Control Methodology is developed for a class of uncertain multi-input multi-output nonlinear systems using linearly parameterized neural networks. The Methodology can be applied to non-minimum phase systems if the non-minimum phase zeros are modeled to a sufficient accuracy. The Control architecture is comprised of a linear Controller and a neural network. The neural network operates over a tapped delay line of memory units, comprised of the system's input/output signals. The adaptive laws for the neural-network weights employ a linear observer of the nominal system's error dynamics. Ultimate boundedness of the error signals is shown through Lyapunov's direct method. Simulations of an inverted pendulum on a cart illustrate the theoretical results.

Dawei Zhang - One of the best experts on this subject based on the ideXlab platform.

  • design and Control Methodology of a 3 dof flexure based mechanism for micro nano positioning
    Robotics and Computer-integrated Manufacturing, 2015
    Co-Authors: Z Guo, Bijan Shirinzadeh, Yanling Tian, C Liu, Fujun Wang, Xianping Liu, Dawei Zhang
    Abstract:

    A 3-DOF (X-Y-?Z) planar flexure-based mechanism is designed and monolithically manufactured using Wire Electro-Discharge Machining (WEDM) technology. The compact flexure-based mechanism is directly driven by three piezoelectric actuators (PZTs) through decoupling mechanisms. The orthogonal configuration in the x and y directions can guarantee the decoupling translational motion in these axes. The rotational motion and translational displacement in the x direction can be decoupled by Controlling the piezoelectric actuators in the x axis with the same displacement values in same and opposite motion directions, respectively. The static and dynamic models of the developed flexure-based mechanism have been developed based on the pseudo-rigid-body model Methodology. The mechanical design optimization is conducted to improve the static and dynamic characteristics of the flexure-based mechanism. Finite Element Analyses (FEA) are also carried out to verify the established models and optimization results. A novel hybrid feedforward/feedback Controller has been provided to eliminate/reduce the nonlinear hysteresis and external disturbance of the flexure-based mechanism. Experimental testing has been performed to examine the dynamic performance of the developed flexure-based mechanism. The mechanical design Methodology for a compact 3-DOF planar flexure-based mechanism has been developed.Influences of the Hertzian contact stiffness on the dynamic performance of the developed mechanism have been explored.A novel hybrid feedforward/feedback Controller has been proposed to reduce/eliminate the hysteresis.

  • a flexure based mechanism and Control Methodology for ultra precision turning operation
    Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology, 2009
    Co-Authors: Bijan Shirinzadeh, Yanling Tian, Dawei Zhang
    Abstract:

    This paper presents the Methodology for modeling and Control of a high precision flexure-based mechanism for ultra-precision turning operation. A high performance piezoelectric actuator is used to driven the flexure-based mechanism. A parallel flexure hinge mechanism is utilized to guide the moving platform and to preload the piezoelectric actuator. A high resolution capacitive sensor is used to measure the displacement of the flexure-based mechanism for closed-loop Control. With consideration of the driving circuit, the dynamic model of the flexure-based mechanism has been established. The effect of the driving circuit on the dynamic response of the precision mechanism is investigated. Experimental tests have been carried out to verify the established model and the performance of the flexure-based mechanism.