A complex control system based on the fuzzy PID control and state predictor feedback control

A multi-mode adaptive controller was proposed. The controller features in the combination of Bang-bang and Fuzzy PID controls with state predictor. When large error exists, the controller operates in Bang-bang mode, otherwise it works as a fuzzy PID controller. For only few parameters to be adjusted, the real time controlled system achieveed good stability and fast response. Furthermore, the introduction of state observer was also discussed to extend the capability of the proposed controller to the plant with time-delay factors. The classical PID controller and the multi-mode controller were applied to the same second-order system successively. By comparison of the simulation results, the effectiveness of the controller were shown. At last, on electric-wire production line, this approach was practiced to control electric-wire diameter with an additive random disturbance signal. The test result further proved the effectiveness of the multi-mode controller.     

Application of predictive control scheduling method to real-time periodic control tasks overrun

Based on the abort strategy of fixed periods, a novel predictive control scheduling methodology was proposed to efficiently solve overrun problems. By applying the latest control value in the prediction sequences to the control objective, the new strategy was expected to optimize the control system for better performance and yet guarantee the schedulability of all tasks under overrun. The schedulability of the real-time systems with p-period overruns was analyzed, and the corresponding stability criteria was given as well. The simulation results show that the new approach can improve the performance of control system compared to that of conventional abort strategy, it can reduce the overshoot and adjust time as well as ensure the schedulability and stability.     

Stability control of steer by wire system based on μ synthesis robust control

The uncertainty influences may result in performance deterioration and instability to the steer by wire(SBW) system. Thus, it must make the control system keep robust stability from uncertainty, and have good robustness. In order to effectively restrain the interference and improve steering stability, this paper presents a μ synthesis robust controller based on SBW system, which considers the effect of model uncertainty and external disturbance on the system dynamics. Taking the ideal yaw rate tracking, interference suppression and excellent robustness as the control objectives, the μ synthesis robust controller is designed using linear fractional transformation theory to deal with the uncertainty. Then, it is testified through time domain and robustness simulation analysis. Simulation results show that the proposed controller can not only ensure robustness and robust stability of the system quite well, but improve handling stability of the vehicle effectively. The results of this study provide certain theoretical basis for the research and application of SBW system.     

Improved H_∞ control for networked control systems with network-induced delay and packet dropout

The H_∞ performance analysis and controller design for linear networked control systems(NCSs) are presented.The NCSs are considered a linear continuous system with time-varying interval input delay by assuming that the sensor is time-driven and the logic Zero-order-holder(ZOH) and controller are event-driven.Based on this model,the delay interval is divided into two equal subintervals for H_∞ performance analysis.An improved H_∞ stabilization condition is obtained in linear matrix inequalities(LMIs) framework by adequately considering the information about the bounds of the input delay to construct novel Lyapunov–Krasovskii functionals(LKFs).For the purpose of reducing the conservatism of the proposed results,the bounds of the LKFs differential cross terms are properly estimated without introducing any slack matrix variables.Moreover,the H_∞ controller is reasonably designed to guarantee the robust asymptotic stability for the linear NCSs with an H_∞ performance level γ.Numerical simulation examples are included to validate the reduced conservatism and effectiveness of our proposed method.     

External stability of fractional-order control systems

Stabilityisapreconditionforcontrolsystemsto operatenormally.Anunstablesystemisnotofpracticalvalueinengineering.Thecontrolsystemsusedsofarareallconsideredinteger ordersystems,althoughtherealobjectsaregenerallyfractional[1].Thereasonto disregardtherealorder…     

Accurate tracking control in LOM application

The fabrication of accurate prototype from CAD model directly in short time depends on the accurate tracking control and reference trajectory planning in (Laminated Object Manufacture) LOM application. An improvement on contour accuracy is acquired by the introduction of a tracking controller and a trajectory generation policy. A model of the X-Y positioning system of LOM machine is developed as the design basis of tracking controller. The ZPETC (Zero Phase Error Tracking Controller) is used to eliminate single axis following error, thus reduce the contour error. The simulation is developed on a Maltab model based on a retrofitted LOM machine and the satisfied result is acquired.     

Prediction control of active power filters

A prediction method to obtain harmonic reference for active power filter is presented. It is a new use of the adaptive predictive filter based on FIR. The delay inherent in digital controller is successfully compensated by u-sing the proposed method, and the computing load is not very large compared with the conventional method. Moreover, no additional hardware is needed. Its DSP-based realization is also presented, which is characterized by time-variant rate sampling, quasi synchronous sampling, and synchronous operation among the line frequency, PWM generating and sampling in A/D unit. Synchronous operation releases the limitation on PWM modulation ratio and guarantees that the electrical noises resulting from the switching operation of IGBTs do not interfere with the sampled current. The simulation and experimental results verify the satisfactory performance of the proposed method.     

Support vector regression-based internal model control

This paper proposes a design of internal model control systems for process with delay by using support vector regression(SVR).The proposed system fully uses the excellent nonlinear estimation performance of SVR with the structural risk minimization principle.Closed-system stability and steady error are analyzed for the existence of modeling errors.The simulations show that the proposed control systems have the better control performance than that by neural networks in the cases of the training samples with small size and noises.     

Advanced control of walking-beam reheating furnace

Reheating furnace is an important device with complex dynamic characteristics in steel plants. The temperature tracing control of reheating furnace has great importance both to the quality of slabs and energy saving. A model-based control strategy, multivariable constrained control (MCC) for the reheating furnace control is used. With this control method, the furnace is treated as a six-input-six-output general model with loops coupled in nature. Compared with the traditional control, the proposed control strategy gets better temperature tracing accuracy and exhibits some energy saving feature. The simulation results show that the performance of the furnace is greatly improved.     

Industrial applications of advanced control techniques

This paper discusses two industrial control applications using advanced control techniques. They are the optimal-tuning nonlinear PID control of hydraulic systems and the neural predictive control of combustor acoustic of gas turbines. For hydraulic control systems, an optimal PID controller with inverse of dead zone is introduced to overcome the dead zone and is designed to satisfy desired time-domain performance requirements. Using the adaptive model, an optimal-tuning PID control scheme is proposed to provide optimal PID parameters even in the case where the system dynamics is time variant. For combustor acoustic control of gas turbines, a neural predictive control strategy is presented, which consists of three parts: an output model, output predictor and feedback controller. The output model of the combustor acoustic is established using neural networks to predict the output and overcome the time delay of the system, which is often very large, compared with the sampling period. The output-feedback c     

Robot motion control in mobile environment

With the problem of robot motion control in dynamic environment represented by mobile obstacles, working pieces and external mechanisms considered, a relevant control actions design procedure has been proposed to provide coordination of robot motions with respect to the moving external objects so that an extension of robot spatial motion techniques and active robotic strategies based on approaches of nonlinear control theory can be achieved.     

Overview of multirate sampled-data control system

0　ＩＮＴＲＯＤＵＣＴＩＯＮＭｕｌｔｉｒａｔｅｓａｍｐｌｅｄ ｄａｔａｓｙｓｔｅｍｓａｒｅｅｎｃｏｕｎｔｅｒｅｄｗｈｅｎｓｏｍｅｓｉｇｎａｌｓｏｆｉｎｔｅｒｅｓｔａｒｅｓａｍｐｌｅｄａｔａｄｉｆｆｅｒ ｅｎｔｒａｔｅｔｈａｎｏｔｈｅｒｓ[1] .Ｍｕｌｔｉｒａｔｅｓｙｓｔｅｍｓａｐｐｅａｒｆｒｅ ｑｕｅｎｔｌｙｉｎｉｍｐｌｅｍｅｎｔａｔｉｏｎｓｏｆｍａｎｙｄｉｇｉｔａｌｃｏｎｔｒｏｌｓｙｓｔｅｍｓ ,ｉｔｓｓｔａｎｄａｒｄｄｉａｇｒａｍｉｓＦｉｇ .1[2 ] .Ｔｈｅｒｅａｒｅｓｅｖｅｒａｌｒｅａｓｏｎｓｔｏｕｓ…     

Preparation and crystallization control of nanoparticle hydroxyapatite

Nanoparticle hydroxyapatite was prepared by a wet chemical precipitation method. The effects of different synthesis conditions, i.e. contents of reagents (0.2, 0.5 and 0.8 mol/L), reaction temperatures (20, 37, 55 and 75℃) and reaction time (0-24h), were studied based on crystallization process analysis and the effects of washing methods (with water or alcohol) were also studied. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), electron diffraction (ED) and inductively coupled plasma spectroscopy (ICP) were used to characterize the powders. Chemical analysis shows that the purity of the precipitated hydroxyapatite largely depends on reaction time. X-ray diffraction and TEM micrographs results show that reaction temperature is a key factor affecting crystallinity, morphology and particle size. Degree of supersaturation and stirring also affects the crystallization. Particles are in a shape of short rod and have a size of 20-40 nm in length at 20℃ and 37℃, but acicular morphology and a size of 150-170nm in length at 75℃. Particles are monocrystalline at 20℃ and 37℃, and are polycrystalline at 55℃ and 75℃. The results show that stoichiometry hydroxyapatite with controlled particle size, morphology and crystallinity can be obtained by carefully controlling the reaction conditions.     

Impulsive orbit control for spacecraft around asteroid

0　INTRODUCTIONExploringsmallbodies ,suchascometsandaster oids ,isoneofthemostsophisticatedmissionscurrentlybeinginvestigatedindeepspaceexploration .Duetothelackofsmallbodyinformationsuchasshape ,mass ,den sitycompositionandrotationaldynamic ,itisachallengetocontroltheorbitofspacecraftaroundsmallbody .NEARmissionofAPLandROSETTAplanofESAbothdealwiththeorbitcontrolofspacecraftaroundsmallbody.Ithasattractedmanyresearcherstostudyonthedynamicalenvironment,theorbitalstablecharacterization…     

Preparation and crystallization control of nanoparticle hydroxyapatlte

Nanoparticle hydroxyapatite was prepared by a wet chemical precipitation method. The effects of different synthesis conditions, i.e. contents of reagents (0.2, 0.5 and 0.8 mol/L), reaction temperatures (20, 37, 55 and 75℃) and reaction time (0-24 h), were studied based on crystallization process analysis and the effects of washing methods (with water or alcohol) were also studied. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), electron diffraction (ED) and inductively coupled plasma spectroscopy (ICP) were used to characterize the powders. Chemical analysis shows that the purity of the precipitated hydroxyapatite largely depends on reaction time. X-ray diffraction and TEM micrographs results show that reaction temperature is a key factor affecting crystallinity, morphology and particle size. Degree of supersaturation and stirring also affects the crystallization. Particles are in a shape of short rod and have a size of 20-40 nm in lengt     

Automobile active suspension system with fuzzy control

A quarter-automobile active suspension model was proposed. High speed on/off solenoid valves were used as control valves and fuzzy control was chosen as control method.Based on force analyses of system parts, a mathematical model of the active suspension system was established and simplified by linearization method. Simula-tion study was conducted with Matlab and three scale coefficients of fuzzy controller (kc,kcc,ku) were acquired.And an experimental device was designed and produced. The results indicate that the active suspension system can a-chieve better vibration isolation performance than passive suspension system, the displacement amplitude of automo-bile body can be reduced to 55%. Fuzzy control is an effective control method for active suspension system.     

TSM control of the delayed input system

The paper proposed a terminal sliding mode control method for the delayed input system with uncertainties. Firstly,through the state transformation,the original system was transformed into the non-delayed controllable canonical form system. Then the paper designed a terminal sliding mode and terminal sliding control law with Lyapunov method for the transformed system. Through the method,the reaching time of the any initial state and the convergencing time to the equilibrium points are constrained in finite time. The simulation results show the validation of the method.     

Macroeconomic control of interest rate in China

0　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｇｏｖｅｒｎｍｅｎｔｓｏｆｔｈｅｍａｉｎｃｏｕｎｔｒｙｏｆｔｈｅｗｏｒｌｄａｌｌｕｔｉｌｉｚｅｔｈｅｐｏｌｉｃｙｏｆｉｎｔｅｒｅｓｔｒａｔｅｔｏｃａｒｒｙｏｎｍａｒｃｏｅｃｏｎｏｍｉｃｒｅｇｕｌａｔｉｏｎａｎｄｃｏｎｔｒｏｌ .Ｔｈｅｃｈａｒａｃｔｅｒｏｆｉｎｔｅｒｅｓｔｒａｔｅｉｓｍｏｒｅｏｂｖｉｏｕｓａｓａｐｏｌｉｃｙｔｏｏｌ,ｂｅｃａｕｓｅｔｈｅｍａｒｋｅｔｅｃｏ ｎｏｍｉｃｓｙｓｔｅｍｉｎＣｈｉｎａｈａｓｎｏｔｔｏｔａｌｌｙｔａｋｅｎｓｈａｐｅｙｅｔ .Ｉｎｒ…     

Modeling and control of hydraulic excavator''''s arm

1 INTRODUCTIONA hydraulic excavator is a multi-functionalconstruction machine ,and is used for excavating,dumping,finishing,lifting work, etc . However ,operators who control hydraulic excavators mustbe trainedfor several years to do such work quicklyand skillfully . A hydraulic excavator has threelinks :boom,dipper and bucket . An operator hasonly two arms . Thus ,it is not easy for beginnersto execute elaborate work that manipulates threelinks at the same ti me . Moreover ,the operator…