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... Tianyou Chai*,**. Heng Yue*,**. Hong Wang***. ... In this paper an intelligent control method for flotation process integrated the ideologies of both modelling and controlling (Chai, Tan, Chen, et al, 2002, Chai, Liu, Ding, and Su,... more
... Tianyou Chai*,**. Heng Yue*,**. Hong Wang***. ... In this paper an intelligent control method for flotation process integrated the ideologies of both modelling and controlling (Chai, Tan, Chen, et al, 2002, Chai, Liu, Ding, and Su, 2007) is proposed to control the concentrate grade ...
Control of nonlinear systems preceded by unknown hysteresis nonlinearities is a challenging task and has received great attention recently due to increasing industrial demands. In the literature, many mathematical models have been... more
Control of nonlinear systems preceded by unknown hysteresis nonlinearities is a challenging task and has received great attention recently due to increasing industrial demands. In the literature, many mathematical models have been proposed to describe the hysteresis. The challenge addressed here is how to fuse those hysteresis models with available robust control techniques to have the basic requirement of stability
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ABSTRACT
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A generalized Prandtl-Ishlinskii model is proposed for modeling hysteresis nonlinearities in piezoceramic actuator. A generalized play operator is presented and integrated to the Prandtl-Ishlinskii model together with density function.... more
A generalized Prandtl-Ishlinskii model is proposed for modeling hysteresis nonlinearities in piezoceramic actuator. A generalized play operator is presented and integrated to the Prandtl-Ishlinskii model together with density function. The generalized play hysteresis operator is analysed using linear envelop function. Parameters identification for the generalized Prandtl-Ishlinskii model is carried out using nonlinear optimization technique. The validity of the generalized model is demonstrated by comparing its displacement responses with the measured responses obtained for piezoceramic actuator.
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... formulations. A generalized model of the hydro-pneumatic suspensions is developed that could be applied for either the roll or pitch plane of the vehicle, permitting analyses of suspension forces in a very simple manner. The ...
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On basis of a modified "on-off" damping law, an inverse model based semi-active damping controller is proposed for implementing an asymmetric control suspension design with symmetric MR dampers. The inverse model control has... more
On basis of a modified "on-off" damping law, an inverse model based semi-active damping controller is proposed for implementing an asymmetric control suspension design with symmetric MR dampers. The inverse model control has potential to compensate the hysteresis effects of MR-damper and realize the semi-active force tracking control. The controller is formulated in current form by integrating a continuous modulation and an asymmetric damping force generation algorithms, so as to effectively minimize the switching transient effects and to realize asymmetric damping forces in compression and rebound from the symmetric MR-damper design. The proposed controller is thoroughly evaluated in terms of defined performance measures under varying amplitude harmonic, rounded pulse and really measured random excitations. The results illustrate that the proposed inverse model based asymmetric semi-active MR-suspension has superior robustness against variations of vehicle load and speed, and the road roughness, and can thus achieve desirable multi-body vehicle suspension performance.
ABSTRACT Smart actuators, such as magnetorestrictive actuators, shape memory alloy (SMA) actuators, and piezoceramic actuators, generally exhibit symmetric and asymmetric hysteresis loops. In this paper, a generalized Prandtl-Ishlinskii... more
ABSTRACT Smart actuators, such as magnetorestrictive actuators, shape memory alloy (SMA) actuators, and piezoceramic actuators, generally exhibit symmetric and asymmetric hysteresis loops. In this paper, a generalized Prandtl-Ishlinskii model with an asymmetric play operator is utilized for describing asymmetric hysteresis nonlinearities in smart actuators. Furthermore, a corresponding inverse of the asymmetric Prandtl-Ishlinskii model is presented as a compensator for the purpose of removing the hysteresis effects in the control systems. Such a compensation is experimentally illustrated by a piezoceramic actuator.
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... of inverse model-based compensation methods have been developed for compensating undesirable effects of actuator hysteresis in tracking and mico/nano-positioning ... M. Al Janaideh is with the Department of Mechatronics Engineering,... more
... of inverse model-based compensation methods have been developed for compensating undesirable effects of actuator hysteresis in tracking and mico/nano-positioning ... M. Al Janaideh is with the Department of Mechatronics Engineering, University of Jordan, Amman, Jordan. ...
ABSTRACT Concepts in roll-interconnected hydro-pneumatic suspensions with hydraulic and pneumatic couplings are developed and analysed for enhancement of anti-roll properties of heavy vehicles. The mathematical models of the roll-coupled... more
ABSTRACT Concepts in roll-interconnected hydro-pneumatic suspensions with hydraulic and pneumatic couplings are developed and analysed for enhancement of anti-roll properties of heavy vehicles. The mathematical models of the roll-coupled suspensions are formulated considering the fluid properties and variable damping valves. The roll properties of fluidically connected suspensions are compared with those of unconnected suspensions with and without anti-roll bar, and dynamic responses of a heavy vehicle with different suspensions are investigated under excitations arising from road roughness and directional manoeuvres. The results indicate that both interconnected suspensions could considerably improve roll stiffness without affecting vertical ride, while hydraulic interconnections could further enhance the roll mode damping properties.
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... The function ( , , ) ce ce ce ce M p ȟ z is formulated in equation (5) to provide smooth transition to the limiting current as the relative position exceeds the margin value. ... | | and | | s b ce ce s s b H G xx p z d xx i δ − = = −... more
... The function ( , , ) ce ce ce ce M p ȟ z is formulated in equation (5) to provide smooth transition to the limiting current as the relative position exceeds the margin value. ... | | and | | s b ce ce s s b H G xx p z d xx i δ − = = − − 11) ...
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ABSTRACT In this paper, the objective is to develop a lower limb exoskeleton to produce a knee position trajectory that will enable a human shank to track any continuous desired trajectory (or constant setpoint). Given a desired... more
ABSTRACT In this paper, the objective is to develop a lower limb exoskeleton to produce a knee position trajectory that will enable a human shank to track any continuous desired trajectory (or constant setpoint). Given a desired trajectory of knee position, Lyapunov-based adaptive fuzzy control is developed to control the human quadriceps femoris muscle undergoing nonisometric contractions. The developed controller through the use of an integral Lyapunov function does not require a muscle model and can be proven to yield asymptotic stability for a nonlinear muscle model and an exoskeleton model in the presence of bounded nonlinear disturbances (e.g., spasticity, fatigue). The controller singularity problem is elegantly solved as it avoids the nonlinear parametrization from entering into the adaptive control and learning control. The performance of the controller is demonstrated through closed-loop experiments on human subjects. The experiments illustrate the ability of the exoskeleton to enable the leg shank to track single and multiple period trajectories with different periods and ranges of motion.
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An intelligent tracking control architecture is proposed for a class of continuous-time nonlinear dynamic sys-tems actuated by piezoelectric actuators. Generally, hysteresis nonlinearity exists in the piezoelectric actu-ator, which may... more
An intelligent tracking control architecture is proposed for a class of continuous-time nonlinear dynamic sys-tems actuated by piezoelectric actuators. Generally, hysteresis nonlinearity exists in the piezoelectric actu-ator, which may cause undesirable inaccuracy. Based on ...
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In this paper the design of adaptive control of rigid-link electrically-driven robot manipulators is addressed in the presence of arbitrary uncertain inertial parameters of the manipulator and the electrical parameters of the actuators.... more
In this paper the design of adaptive control of rigid-link electrically-driven robot manipulators is addressed in the presence of arbitrary uncertain inertial parameters of the manipulator and the electrical parameters of the actuators. In contrast to the known methods, the presented ...
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... 7@). The displacement response with the passive open-loop damper reveals oscillations at ... The results suggest that the proposed semi-active force tracking PI control can provide ... The controlled vehicle suspension system actuated... more
... 7@). The displacement response with the passive open-loop damper reveals oscillations at ... The results suggest that the proposed semi-active force tracking PI control can provide ... The controlled vehicle suspension system actuated by the MR-damper, inevitably, exhibits strong ...
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In this paper, adaptive neural network control is investigated for single-master-multiple-slaves teleoperation in consideration of time delays and input dead-zone uncertainties for multiple mobile manipulators carrying a common object in... more
In this paper, adaptive neural network control is investigated for single-master-multiple-slaves teleoperation in consideration of time delays and input dead-zone uncertainties for multiple mobile manipulators carrying a common object in a cooperative manner. Firstly, concise dynamics of teleoperation systems consisting of a single master robot, multiple coordinated slave robots, and the object are developed in the task space. To handle asymmetric time-varying delays in communication channels and unknown asymmetric input dead zones, the nonlinear dynamics of the teleoperation system are transformed into two subsystems through feedback linearization: local master or slave dynamics including the unknown input dead zones and delayed dynamics for the purpose of synchronization. Then, a model reference neural network control strategy based on linear matrix inequalities (LMI) and adaptive techniques is proposed. The developed control approach ensures that the defined tracking errors conve...
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In this paper, we present a delay-dependent robust model predictive control (MPC) algorithm for a class of discrete-time linear state-delayed systems subjected to polytopic-type uncertainties and input constraints. The state-feedback MPC... more
In this paper, we present a delay-dependent robust model predictive control (MPC) algorithm for a class of discrete-time linear state-delayed systems subjected to polytopic-type uncertainties and input constraints. The state-feedback MPC law is calculated by minimizing an upper bound of the worst-case quadratic cost function over an infinite time horizon at each sampling instant. In contrast to existing robust MPC techniques, the main advantage of the proposed approach is that the algorithm is derived by using a descriptor model transformation of the time-delay system and by applying a result on bounding of cross products of vectors. This has significantly reduced the conservativeness. It has been shown that robust stability of the closed-loop system is guaranteed by the feasible MPC from the optimization problem. The effectiveness of the algorithm is demonstrated by a simulation.
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Grinding product particle size (GPPS) of grinding circuit (GC) is an important performance index directly related to the product concentrate grade and metal recovery rate. However, it is hard to control effectively with conventional... more
Grinding product particle size (GPPS) of grinding circuit (GC) is an important performance index directly related to the product concentrate grade and metal recovery rate. However, it is hard to control effectively with conventional process control strategies due to its complex characteristics. In this paper, an intelligent supervisory control (ISC) approach of GC is developed by employed intelligent techniques, such as fuzzy and artificial neural network (ANN). This DCS-based ISC system consists of a fuzzy adjuster, an ANN-based GPPS prediction module and an expert interface, and is used to supervise the grinding system and to adjust the setpoints of lower level control loop automatically. The outputs of these loops can therefore track their renewed setpoints so that a desired and optimized GPPS can been achieved. Industrial experiments show the effectiveness of the proposed ISC approach.
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The high conventional accuracy of pattern recognition-based surface myoelectric classification in laboratory experiments does not necessarily result in high accessibility to practical protheses. An obvious reason is the effect of signals... more
The high conventional accuracy of pattern recognition-based surface myoelectric classification in laboratory experiments does not necessarily result in high accessibility to practical protheses. An obvious reason is the effect of signals of untrained classes caused by the relatively small training dataset. In order to make the classifier robust to untrained classes, a classification scheme is developed based on boosting and random forest classifiers in this paper. Meanwhile, a threshold, the post probability of the prediction, is introduced as a balance (i.e., adjust) between the accurate classification and the rejection of the samples belonging to some untrained classes. The experiments are conducted to compare with other two schemes using linear discriminant analysis and support vector machines. Surface electromyogram signals, labeled with seven isometric movements, are collected from six healthy subjects' forearm. It is shown that the proposed scheme can reach up to about 92%...
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In this study, we investigate the efficacy and safety of intraocular use of fluconazole in the treatment of ocular fungal infection. Ten patients with intraocular fungal infections were examined. Among these patients, eight were infected... more
In this study, we investigate the efficacy and safety of intraocular use of fluconazole in the treatment of ocular fungal infection. Ten patients with intraocular fungal infections were examined. Among these patients, eight were infected with keratomycosis with intraocular spreading, one had postoperative fungal endophthalmitis after cataract operation with an intraocular lens implant, and another suffered from endogenous fungal endophthalmitis. In addition to the conventional local application with or without systemic administration of antifungal drugs, all ten patients were treated with intraocular administration of 5-10 micrograms/ml of fluconazole. The ocular fungal infections resolved in nine patients without obvious side effect. One failed in the antifungal treatment with loss of vision. In our experience, the results revealed that fluconazole is a safe and effective antifungal agent that can be administered intraocularly. We suggest that intraocular administration of this dru...