Transfer Function Of Control System Research Articles

An Adaptive Actuator Driver for AC Contactors

The actuator drivers are rarely transplanted among different contactors because the self-tuning of excitation control parameters either takes a long time or is relevant to many contactor structural parameters. An adaptive actuator driver for AC contactors is proposed based on the coil impedance estimation and mathematical equations between the coil impedance and excitation control parameters. The coil impedance estimation and its error correction are established through the voltage balance equation when the contactor is in the open position. The coil inductance estimation is established through the zero-state response equation when the contactor is in the closed position. The mathematical equations are established based on the equivalence of the electromagnetic force under different excitation methods, the power consumption model, and the control system's transfer function. A geometric feature of the flux linkage waveform is established to identify whether a contactor is in the closed position and realize the self-transition of the driver's working state. Then, self-tuning regulators for the excitation control parameters are realized. This driver has a plug-and-play function for AC contactors and can reduce the contactor's power consumption. This driver may be prospectively reduced to a chip.

Design and analysis of root locus based controllers

The root locus method is the classical method for analyzing the variation of the position of the poles of a closed-loop control system transfer function in the complex plane. It is also the basis for guiding the design of various controllers. Starting from the nature of the root locus, this paper takes a standard form of closed-loop feedback control system as an example, and analyzes in detail the internal logic of designing a controller and compensator by the root locus method. At the same time, software such as MATLAB/Simulink, and Octave are used. The working principles and properties of the PD controller; the lead and lag compensator, their interconnections, advantages, and characteristics, as well as the adjustment of parameters to better suit practical needs, are sorted out. The PD controller improves the system response, the lead compensator eliminates the PD controller’s defects, and the lag compensator reduces the steady-state error of the system. It provides help for understanding the essence of controller design and provides design ideas for control problems in actual engineering.

Study of parallel operation of diesel generators ship power plant

Analysis of the power plants of a number of passenger ships showed the need to ensure the parallel operation of generators previously operating separately. The installed DGs are intended only for autonomous operation, which do not imply the introduction of statism into the characteristics of the generators. The aim of the work is to ensure the working condition of the ship power plants in accordance with the current requirements of the Russian River Register (RRR), which imply stable parallel operation of the diesel generator. As a result of the operation of the installed diesel engines, the complexity of precise control of the mechanical characteristics was determined, associated with the specifics of the operation of the mechanical frequency controllers installed on the engines. To determine the quality of mechanical RFI, functional and structural diagrams of the system for stabilizing the frequency of rotation of a drive motor with a mechanical regulator were developed, on the basis of which the transfer function was obtained and a conclusion was made about the instability of the regulator at large values of backlash in the mechanical transmission. Achieving this goal is possible by replacing the mechanical RFI with an electronic one with an actuator, which is confirmed by a mathematical analysis of the corresponding control systems. The transfer functions of control systems are obtained on the basis of the developed structural and functional models. Electronic controllers, made according to the presented schemes, have been introduced on a number of marine diesel generator sets and have shown a positive result. As a result of the study of the operation of the new system, the optimal parameters of the regulator settings were determined, at which the required dynamic and static characteristics were obtained. The failure-free operation of the system has been confirmed by long-term tests with the vessel operating in normal mode throughout the navigation.

Identification of dynamic stiffness and damping in active magnetic bearings using transfer functions of electrical control system

The dynamic rotor behavior is significantly affected by the stiffness and damping characteristics of the bearings. Therefore, it is important to identify these bearing parameters. For active magnetic bearings (AMBs), these bearing parameters not only could be identified from rotor dynamic response, but also from electrical control system transfer function. Some identification works from rotor dynamic response have been reported, but identification from electrical control system transfer function is relatively few. In this paper, we deduced the equivalent stiffness and damping expressions with electrical control system transfer function for rotor AMBs and identified these values from electrical control system model. To evaluate the identified results, previous reported results from rotor dynamic response is employed for comparison. We found that for the stiffness, a complete and precise electrical control model will obtain relatively consistent values; however, for the damping, the accurate electrical control model is still not enough and the eddy current loss should be included.

Study on the Corresponding Relationship Between Dynamics System and System Structural Configurations—Develop a Universal Analysis Method for Eliminating the RHP-Zeros of System

The purpose of this paper is to use bond graphs to retain system structures, linking dynamic models and the transfer functions of control systems, and develop a universal analysis method for eliminating the right-half-plane zeros (RHP-zeros) of systems. Although previous literature has investigated RHP-zero elimination, their findings were only applicable to specific systems. When such a system is modified, only a trial-and-error method can be applied to eliminate the RHP-zeros of systems. The main feature of the proposed method involves the analysis of the causal paths contained in bond graphs. Analysis results then serve as a guideline for RHP-zero elimination, which can involve processes including modification of model structures or changes to paths. This method improves the system to get a better performance, instead of using the trial-and-error methods. Finally, a boost converter with an RHP-zero is applied to various examples of RHP-zero elimination, verifying that the proposed methodology can be used to eliminate the RHP-zeros of systems without the need of a trial-and-error process.

특이값분해를 이용한 PMSM 드라이버 인버터 스위치의 고장 진단 및 분리

Motors are important actuators these days and the fault issues on it are very important for the economy and safety. This paper proposes a new fault detection and isolation method for motor drive inverter switch and it is applied to the PMSM driver. This method is based on the SVD (Singular Value Decomposition) of closed loop motor control system transfer function in frequency domain. The current command which is the input of the closed system is expressed as the linear combination of the right singular vector of the SVD. The parameter vector which perform the linear combination can be also acquired from the out current with the operation of right singular vector and singular value matrix on it. When fault occurs in inverter switch, the parameter vector acquired from current command is different from the one acquired from the output current. This property enables us to detect the fault in inverter switch. And the proposed method can isolate the fault, which means the group of faulted switch is identified. Through simulation, the validity and usefulness are presented.

Design and Construction of a GSM-Controlled Pick and Place Robot

The modern manufacturing environment is dynamic and uncertain. In line with the global trend in manufacturing, this project is carried out to explore into the potentials of robots in manufacturing, service industry, and domestic use. The robot was designed and constructed to incorporate the use of mobile phones as control mechanism via dual-tonemultiple frequency (DTMF). Various components such as the Gripper, Gears, Chains, and Control system were designed with good factor of safety; with factors such as vibration, inertia concerns, availability, and reliability taken into consideration. MATLAB software was used extensively in the design, simulation and testing. The Root-locus, Disturbance response, and Polar plots of the control system transfer function were plotted using MATLAB. The results obtained showed good performance characteristics; such as stability of the control system, good damping characteristics, and excellent time response to step and impulse inputs.

Study on the Transfer Function Test Method for Electro-Optical Tracking Servo Control System

The error of gain of servo control system transfer function is larger by the method of frequency measurement, In this paper, By appying voltage on the both ends of the motor, measure DC response of system to tmeasure the DC gain of control object.Experimental results show that the gain accuracy by the measurement method increases 2.5 times than the traditional measurement.

1010 モーメント法を用いたモデルマッチングによる蒸留塔の PID 制御

This paper deals with the design of PID controller by means of the moment method. Moment method is an approach based on estimated moments of the control object that conform as possible as a transfer function of control system to a reference system model. This design method is applied to the temperature control of a distillation column. In this study moments are derived from ARMAX model based on operational data. Simulation of PID control system design proposed here shows very good results.

Effect of Shaft Flexibility on Control System Parameters

A dynamic system consisting of a servomotor, elastic shaft and inertial load, which may represent a disk or a robot arm, is chosen as an elastic control system. Equations of the torsional vibratory system are coupled with the servomotor control system equations and the transfer function of the elastic control system relating output angle to the desired input angle is obtained including not only control parameters but also the structural natural frequency and the structural damping of the torsional vibratory system. The ratio of the structural natural frequency to the substructural natural frequency and the ratio of substructural natural frequency to the control system frequency are defined as nondimensional parameters. System behavior is analyzed with respect to these parameters. The fourth order elastic control system transfer function is also reduced to the second order one and formulas for elastic control system frequency and damping are developed with respect to these parameters. [S0739-3717(00)70104-8]

Simplifying controller for process control of systems with large dead time

Large dead time is a significant control problem and source of instability for the control loop. A Smith Predictor scheme provides a conventional large dead time compensation leaving other process dynamics to the separate controller. The real long dead time processes, such as heat transfer and flow control systems, typically exhibit long time delays intertwined with other process dynamics. One of the authors, Roman Gorecki, proposed and implemented a new algorithm, based on the principle of simplification of the control system transfer function, to deal with this issue. The concept of this new algorithm, called a Simplifying Controller, is briefly presented. It is followed by the real system example where a heat transfer process control system with use of the Simplifying Controller is described. The Simplifying Controller algorithm offers improved control for large dead-time process control applications.

Generalized transfer function of control system and an improvement on the decision method of movement stability

In this paper the definitions of generalized transfer function of control system and its continuity are presented. Using generalized transfer function as a tool, a set of theorems for deciding movement stability have been constructed. Thus basing our understanding of the characteristics of a control dynamics system on its measured procedure will simplify the decision method of movement stability problems

Minimization of reactor noise through external control

An analytical approach based on the work of Wiener is taken to develop an expression for an optimum linear feedback control system that will minimize the random variations in the flux of a nuclear power reactor. The optimization criterion is the minimization of the mean-square value of these random variations. In determining the optimum control system transfer function, an acceleration constraint is placed on the control-rod drive mechanism. To demonstrate the technique presented, an optimum control system transfer function is derived for the experimental boiling water reactor (EBWR) under specified operating conditions. The changes in the mean-square value of reactor flux caused by varying acceleration constraint level is discussed. Results show that a considerable reduction in the mean-square value of the random flux variations can be obtained through external control.

Control systems with minimum spectral bandwidth of plant input

A design method for control systems that minimizes the spectral bandwidth of the plant input signal is discussed. The plant input signal is minimized subject to the constraint that the integral square error for deterministic inputs or the mean square error for random inputs be limited to a known desired value. The control system transfer function that satisfies these requirements is derived, and the functions used in bandwidth shaping are discussed. An example of a system design using this technique is given.