Reference Control System Research Articles

Mixed H2/H∞ model reference control of linear parameter‐varying discrete‐time systems with real‐time application to aeropendulum system

AbstractThe investigation of this paper revolves around the problem of designing mixed model reference control (MRC) systems of linear parameter‐varying discrete‐time systems. In this paper, two types of mixed MRC systems are considered. These two types are the mixed state‐feedback and the mixed dynamic output‐feedback MRC systems that are designed using a parameter‐dependent Lyapunov function. The experimental results of the aeropendulum system are used to evaluate and show the effectiveness of the proposed controllers. The results indicate the satisfactory performances of the closed‐loop systems.

Design of Adaptive Estimator for Nonlinear control system in Noisy Domain

In the recent research studies, adaptive control has been used to monitor a reference control system that has been selected by the researcher. The acceptable reference system can be executed with the presence of nonlinearity and undesirable switches, as they have been disabled. This research study examines the challenges in adapting the state and time-varying parameters, when noise and state disturbances are present in a nonlinear control system. Additionally, this adaptive controller points out the best or most accurate option based on recursive least squares calculations by using the sensor data. This convergence has a rate of arrival with a set time of origin that serves as an estimate for error estimation. In addition, this research work has evaluated the amount of variance in the estimate, which has been caused by external disturbances using adaptive estimators from the reference value present in the noisy domain. The findings obtained via simulation demonstrate the performance of the adaptive estimator through the difference obtained between the reference value and observed value.

Wireless stepper motor control and optimization based on robust control theory

<img src="blob:http://ijra.iaescore.com/f3842e5c-715f-4e1e-9ffd-952309f5ccb1" alt="" />Stepper motors are broadly utilized in actual systems, which are marked by non-linear parameters such as internal, external noises and uncertainties from wireless network. As well, a suitable controller is required when the problem is to track the target signal. In this paper, robust controller based on model reference are investigated to wireless control and optimize position and time in stepper motors. The core impression to build a robust controller is to use a model reference control system. Furthermore, simulations are implemented to control stepper motor position and time in two cases: first, when the wireless network without any delay and packet dropout. Second, uncertain equations when the wireless network with time delays and packet dropout. Simulation results demonstrate that proposed controller has achieved and enhanced the performance in tracking and robustness.

Vibrating Coordinates Frame Transformation Based Unity Power Factor Control of a Three-Phase Converter at Grid Voltage Imbalance and Harmonics

This article proposes a control system of a three-phase grid-connected power converter, operating in the rectifier mode, which achieves the unity power factor target, i.e., unbalanced and distorted current instead of sinusoidal one for grid voltage imbalance and harmonics. Such a target is known from active power filters control, but it has not been used for power supply devices yet. Thanks to that, the three-phase converter is seen as resistive load by the utility grid, and active power is consumed with minimal possible rms current, keeping current asymmetry corresponding to the voltage asymmetry during unbalanced dips. Intentional introduction of current harmonics is not trivial from the point of view of both reference signals calculation and control system structure, because in the classical approach, it would require resonant terms in controller structure. Additionally, grid voltage asymmetry introduces another oscillating component, which imposes other resonant terms in the controller. The transformation presented in this article allows to achieve desirable current harmonics and asymmetry with the use of two proportional-integral controllers, one in each controlled axis. This article presents theoretical principles of the new transformation, control system structure as well as simulation and experimental tests of a three-phase converter utilizing this idea.

Mechanical design and finite element analysis of live working robot for 10kV distribution power systems

Abstract Live-working is the development trend of smart grid, and the development of high-performance live-working robot system is the inevitable demand of technology development. A dual-arm live-working robot system is developed to overcome the problems existing in the design and application of the current live-working robots. The system is composed of operation module, reference board platform module, insulation cover and control system module. The power-driven cooperative UR10 mechanical manipulators are used, and standardized mechanical interfaces are adopted to make sure that the assembly and testing process is very efficient and convenient. ANSYS Workbench is used to analyze the strength of the whole robot to guarantee the requirements of strength and deformation. The mass of the whole robot is minimized to less than 170kg during the lead wire procedure.

Optimizing of phase plan, sequence and signal timing based on flower pollination algorithm for signalized intersections

The purpose of this study is to develop a control system that optimizes the phase plan, sequence and signal timing using the flower pollination algorithm (FPA). At the same time, it is aimed to improve the fixed-time control system with the optimum cycle length search approach based on the differential evolution algorithm. The applicability and performances of these two control systems were examined in 15 different traffic situations according to 4 different intersection geometries. Fixed-time and optimized fuzzy logic traffic controller (FLC) developed by Dogan were used as the reference control systems in performance comparison. The optimum cycle length search system can achieve approximately 18% improvement over the fixed-time system, but showed lower performance than the FPA and FLC control systems. The FPA system has proven its applicability by achieving the best performance with about a 30% improvement compared to the fixed-time system and about 3% improvement compared to the FLC system. The FPA approach, which has a fast and effective performance, has been found to be an alternative method for intersection control, and it is foreseen that it can increase the intersection capacity and reduce the negative effects such as delay and fuel consumption.

Wearable multichannel haptic device for encoding proprioception in the upper limb

Objective. We present the design, implementation, and evaluation of a wearable multichannel haptic system. The device is a wireless closed-loop armband driven by surface electromyography (EMG) and provides sensory feedback encoding proprioception. The study is motivated by restoring proprioception information in upper limb prostheses. Approach. The armband comprises eight vibrotactile actuators that generate distributed patterns of mechanical waves around the limb to stimulate perception and to transfer proportional information on the arm motion. An experimental study was conducted to assess: the sensory threshold in eight locations around the forearm, the user adaptation to the sensation provided by the device, the user performance in discriminating multiple stimulation levels, and the device performance in coding proprioception using four spatial patterns of stimulation. Eight able-bodied individuals performed reaching tasks by controlling a cursor with an EMG interface in a virtual environment. Vibrotactile patterns were tested with and without visual information on the cursor position with the addition of a random rotation of the reference control system to disturb the natural control and proprioception. Main results. The sensation threshold depended on the actuator position and increased over time. The maximum resolution for stimuli discrimination was four. Using this resolution, four patterns of vibrotactile activation with different spatial and magnitude properties were generated to evaluate their performance in enhancing proprioception. The optimal vibration pattern varied among the participants. When the feedback was used in closed-loop control with the EMG interface, the task success rate, completion time, execution efficiency, and average target-cursor distance improved for the optimal stimulation pattern compared to the condition without visual or haptic information on the cursor position. Significance. The results indicate that the vibrotactile device enhanced the participants’ perceptual ability, suggesting that the proposed closed-loop system has the potential to code proprioception and enhance user performance in the presence of perceptual perturbation.

Robust model reference control of linear parameter‐varying systems with disturbances

This paper deals with the design and analysis of robust model reference control systems for a class of linear parameter-varying (LPV) systems with disturbances. Two types of robust model reference control systems are proposed to achieve a prescribed tracking performance. The first type is the LPV H ∞ state-feedback model reference control system and the second type is the LPV H ∞ output-feedback model reference control system. Based on the notion of quadratic stability, necessary and sufficient conditions for the existence of LPV reference models are given. Also, a parameterisation of LPV reference models is derived in this study. A practical example of a single-link flexible-joint robot is given to illustrate the design steps and to show the effectiveness of the proposed LPV H ∞ model reference controllers.

Self-corrected chip-based dual-comb spectrometer.

We present a dual-comb spectrometer based on two passively mode-locked waveguide lasers integrated in a single Er-doped ZBLAN chip. This original design yields two free-running frequency combs having a high level of mutual stability. We developed in parallel a self-correction algorithm that compensates residual relative fluctuations and yields mode-resolved spectra without the help of any reference laser or control system. Fluctuations are extracted directly from the interferograms using the concept of ambiguity function, which leads to a significant simplification of the instrument that will greatly ease its widespread adoption and commercial deployment. Comparison with a correction algorithm relying on a single-frequency laser indicates discrepancies of only 50 attoseconds on optical timings. The capacities of this instrument are finally demonstrated with the acquisition of a high-resolution molecular spectrum covering 20 nm. This new chip-based multi-laser platform is ideal for the development of high-repetition-rate, compact and fieldable comb spectrometers in the near- and mid-infrared.

Learning vector quantization neural network–based model reference adaptive control method for intelligent lower-limb prosthesis

This article focuses on the design of a control system for intelligent prostheses. Learning vector quantization neural network–based model reference adaptive control method is employed to implement real-time trajectory tracking and damp torque control of intelligent lower-limb prosthesis. The method is then analyzed and proposed. A model reference control system is first built with two learning vector quantization neural networks. One neural network is used for output prediction, and the other is used for input control. The angle information of the prosthetic knee joint is utilized to train these two neural networks with the given learning algorithm. The testing results of different movement patterns verify the effectiveness of the proposed method and its suitability for intelligent lower-limb prostheses.

Design of Robust Fractional PID Controller Using Triangular Strip Operational Matrices

Abstract The present article proposes a simple tuning technique aimed to produce a robust non-integer order PID controller exhibiting iso-damping property during reparameterization of a plant. The required robustness property is achieved by letting the fractional PID control system to imitate the dynamics of a reference system having Bode’s ideal transfer function in its forward path. The objective of designing robust controller by tracking the dynamics of reference control system is defined mathematically as an H∞- optimal control problem. Fractional differential systems are transformed into algebraic equations by the use of triangular strip operational matrices. The H∞-optimal control problem is then changed to an ∞-norm minimization of a parameter (Kc,KI,Kd, λ, μ) varying square matrix. Global optimization techniques, Luus-Jaakola direct search and particle swarm optimization are employed to find the optimum values of fractional PID controller parameters. The proposed method of control system design is implemented in heating furnace temperature control, automatic voltage regulator system and some integer and fractional order process models. Fractional PI, fractional PD and various versions of fractional PID controllers are designed as optimal controllers using the triangular strip operational matrix based control design method.

UV-cured methacrylic-silica hybrids: Effect of oxygen inhibition on photo-curing kinetics

The kinetic behavior of innovative photopolymerizable UV-cured methacrylic–silica hybrid formulations, previously developed, was studied and compared to that of a reference control system. The organic–inorganic (O–I) hybrids proposed in this study are obtained from organic precursors with a high siloxane content mixed with tetraethoxysilane (TEOS) in such a way to produce co-continuous silica nano-domains dispersed within a cross-linked organic phase, as a result of the hydrolysis and condensation reactions. The kinetics of the radical photopolymerization mechanism induced by UV-radiations, in presence of a suitable photoinitiator, was studied by calorimetric, FTIR and Raman spectroscopic analyses, by varying the composition of the mixtures and the atmosphere for reactions. The well known effect of oxygen on the kinetic mechanism of the free radical photopolymerization of the methacrylic–siloxane based monomers was found to be strongly reduced in the hybrid system, especially when a proper thiol was used. The experimental calorimetric data were fitted using a simple kinetic model for radical photopolymerization reactions, obtaining a good agreement between the experimental data and the theoretical model. From the comparison of the kinetic constants calculated for control and hybrid systems, it was possible to assess the effect of the composition, as well as of the atmosphere used during the photo-polymerization process, on the kinetic of photopolymerization reaction.

Fuzzy Control of a Novel Type of Translational Meshing Motors

Owing to the nonlinear characteristic of a novel type of translational meshing motor with model uncertainties, a model reference control system which consists of a neural network and a fuzzy controller is used. The torque model is identified based on BP neural network, and then Fuzzy controller works as the controller. The description of the control system and training procedure of the neural network are given. The test results obtained for a torque control scheme suitable for the control of the motor are also presented to verify the effectiveness of the proposed nonlinear control scheme. It has been found that the fuzzy control system is able to work reliably.

Composite Loads in Stand-Alone Inverter-Based Microgrids—Modeling Procedure and Effects on Load Margin

This paper details a modeling procedure that incorporates composite loads in stand-alone microgrids in which, because of the low system inertia provided by inverter-interfaced generation units, the grid dynamics is not neglected. The paper introduces a methodology based on 1) separately treating the plants (RL grid elements) from reference frames and control systems; and 2) establishing a vector valued function to methodologically describe all plants in a similar way. Induction motors equations are rearranged to be integrated within the model, giving as a result a highly structured, compact system model. Next, bifurcation theory is adapted to the problem to show that composite loads are a need in the microgrid modeling if more realistic results about oscillations and mainly about load margin are pursued. Thanks to the modeling procedure, this is proven by means of a series of analyses conducted in a microgrid of considerable larger dimensions than those presented to date in the literature.

Transient response improvement of feedback control systems using hybrid reference control

By means of the internal model principle, an approach to improve the performance of a stabilised closed-loop continuous time linear system based on manipulation of the reference signal is developed. A change in the reference signal is equivalent to implementing an instantaneous change via the choice of a decision vector in the state of the reference signal model, and the analysis of the proposed approach called hybrid reference control (HRC) system is then shown to be equivalent to the analysis of a linear impulsive dynamical system. Conditions for asymptotic stability and convergence of the output tracking error for a HRC system are expressed in term of conditions on the decision vectors. Conditions are then derived which guarantee that the HRC system leads to an improved transient performance compared to a conventional closed-loop control system. In particular, it is shown how decision vectors are chosen so that a HRC system results in a deadbeat response.

Definition and execution of a generic assembly programming paradigm

PurposeThis paper aims to introduce a generic robot‐programming paradigm for assembly tasks that overcomes the strong coupling between the motion commands and underlying algorithms of programming languages currently on the market. Therefore, it allows an improved method of assembly task programming.Design/methodology/approachA manipulation primitive (MP) is defined which decouples the programming concept from the algorithms. These primitives can be integrated into existing programming languages and are supported by an intuitive graph‐based language which is introduced in this paper. An open reference architecture to support those primitive‐based programming languages has been designed.FindingsIt is possible to describe complex assembly tasks such as manipulation on conveyors or sensor‐integrated compliant motion without abandoning the generality of the programming paradigm. Execution on a reference control system has proven to be successful for several manipulation tasks on different machines.Originality/valueA complete definition of the MP and a graphical language based on this primitive is given, accompanied by extensive detail information on crucial aspects of the control architecture such as modular trajectory generation, generic interfaces, and real‐time task scheduling.

Development of Power-Assisted Wheelchair with H.INF. Control to Maintain Robustness Against Load Uncertainty

In this paper, a power-assisted wheelchair to support helpers is presented. The model reference control system is proposed such that the wheelchair comfortably moves at the ideal speed with helper's weak force, and H infinity controller is implemented in order to highly maintain the control quality regardless of the disturbance such as the variation of a passenger's mass or the slope of the road. The effectiveness of the proposed system is validated through various experiments such as the comparison with the PI controller, change of patient, the up-and down-slope, and the rotary motion.

An Adaptive Tuning Strategy of PID Attitude Control System

This paper describes a procedure for tuning PID attitude control system of a launch vehicle. The key idea is a method based on a model reference adaptive system to estimate PID control gains. The launch vehicle is considered a rigid body. Since the performance specification is considered as a second order system and the close loop of the launch vehicle PID attitude control system has fourth order with two zeros, there is no matching between model reference and launch vehicle control system. The simulation results of the proposed tuning method are compared with a LQR method.

Assessment of mechatronic system performance at an early design stage

For conceptual design of electromechanical motion systems, an assessment method is formulated that supports the design of a feasible reference path generator, control system, and electromechanical plant with appropriate sensor locations, in an integrated way. This method is based on a classification of standard transfer functions, plant models, and closed-loop systems. The assessment method can be applied in several ways, depending on the available knowledge about the design problem. In order to illustrate this method, an application to an industrial motion system is described. The assessment method quickly provides insight in the design problem. Furthermore, feasible goals and required design efforts can be estimated at an early stage.

Robust Model Reference Control Systems with Online Adjustable Parameters

In this paper, we consider a design of the model reference control systems with adjustable parameters for linear systems with time-varying parametric uncertainties. To discuss this problem, we focus on the output error between the plant and the reference model, and adopt the reachable domain of this error as a performance index. This reachable domain is known as an output reachable set. Based on the analysis technique of output reachable sets, we propose a new design technique of the model reference controller, and demonstrate its efficacy by numerical case studies.