Robust Pole Assignment of Digital Control System with Output Multirate Sampled

Multirate digital control system is a periodically time-variant (PTV) system in its essence. It bas many' super capability', such as obtaining arbitrarily-large gain- margin, simultaneous stabilization, strong stabilization, decentralized control, etc. Utilizing freedom aroused from the multirate sampling of system output, this paper assigns poles of the closedloop system robustly, and so improves the resistance of the system to perturbation.

Digital control system for pulsed MIG welding power based on STM32

Digital control system for pulsed MIG welding power based on STM32 is set up with 32-bit STM32FlO3ZET6 directing against the pulse waveform modulation of pulsed MIG welding. High-frequency inverter and medium-low frequency pulse waveform modulation of pulsed MIG welding are realized by using the integrated PWM module within STM32 to generate PWM signals of phase-shifted full-bridge soft-switching and constant-current control of output current is achieved by means of anti-windup PI control algorithm to improve the stability and reliability of control system. Experimental results demonstrate that the designed digital control system based on STM32 can achieve pegrect pulsed MIG welding technique with stable welding process and good weld appearance, fully demonstrating the advantages of digital control based on STM32.

Control Strategies for Digital Twin Systems

With the continuous breakthrough in information technology and its integration into practical applications, industrial digital twins are expected to accelerate their development in the near future. This paper studies various control strategies for digital twin systems from the viewpoint of practical applications.To make full use of advantages of digital twins for control systems, an architecture of digital twin control systems, adaptive model tracking scheme, performance prediction scheme, performance retention scheme, and fault tolerant control scheme are proposed. Those schemes are detailed to deal with different issues on model tracking, performance prediction, performance retention, and fault tolerant control of digital twin systems. Also, the stability of digital twin control systems is analysed. The proposed schemes for digital twin control systems are illustrated by examples.

Frequency Control System with Digital Signal Processing Techniques

The frequency of digitally controlled iodine stabilized He-Ne laser locked to a hyperfine component in ^127I2 was measured using the National Metrology Institute of Japan＇s reference iodine stabilized He-Ne laser. This laser is operated under the conditions of the practical implementation and its frequency with respect to the International Committee for Weights and Measure recommended value is known from international comparisons. Adopting a sampling rate of 120 kHz for the control system of an iodine stabilized He-Ne laser enables frequency deviation of the test laser from the reference laser by ＋ 5 kHz （relative accuracy of 1 ×10^11） thus limited only by the reproducibility of the iodine stabilized He-Ne laser itself.

Study of modeling and simulation of full digital controlled PMIG/MAG welding system based on Matlab/Simulink

This paper presents an integrated simulation model for full digital controlled PMIG/MAG welding system with Matlab/Simulink, and it consists of power inverter, digital control system and dynamic arc-load model. An integrated simulation study was done for full digital PMIG/MAG welding, and a method of connecting dynamic arc-load model to the system with controlled current source was presented, in addition, the simulation results were utilized to study the issues of digital control PMIG/MAG welding in this paper. The experimental results validated the developed simulation model, and this simulation study can be applied in implementation of the full digital PMIG/MAG welding and analysis of system dynamic process.

Design and Experimental Evaluation of PID Controller for Digital Electro-Pneumatic Cabin Pressure Control System

The performance of the designed digital electro-pneumatic cabin pressure control system for the cabin pressure schedule of transport aircraft is investigated.For the purpose of this study,an experimental setup consisting of a simulated hermetic cabin and altitude simulation chamber is configured for cabin pressure control system operation.A series of experimental tests are executed to evaluate the performance of the cabin pressure control system.The parameters of the PID controller are optimized.In the optimization process,the variation regularity of the rate of cabin pressure change under various conditions is considered.An approach to prioritize the control of the rate of change of cabin pressure based on the flight status model is proposed and verified experimentally.The experimental results indicate that the proposed approach can be adopted for the designed digital electro-pneumatic cabin pressure control system to obtain a better cabin pressure schedule and rate of cabin pressure change.

Finite-time Feedback Stabilization of a Class of Input-delay Systems With Saturating Actuators via Digital Control

In this paper, the problem of making an input-delay system with saturating actuators finite-time stable by virtue of digital control is investigated. A digital state feedback controller and digital observer-controller compensator are designed for two cases: when the state of the input-delay system are available or when it is unavailable. Sufficient conditions which guarantee finite-time stability of a closed-loop input-delay system are given and the proof procedure is presented in a heuristic way by constructing appropriate comparison functions. The condition can be transformed into the intersection of two curves satisfying some constraints, which reveals the relationship between designed parameters clearly. Finally, simulation results are presented to validate the method proposed in this paper.

Design and Implementation of Digital Fractional Order PID Controller Using Optimal Pole-Zero Approximation Method for Magnetic Levitation System

The aim of this paper is to employ fractional order proportional integral derivative(FO-PID)controller and integer order PID controller to control the position of the levitated object in a magnetic levitation system(MLS),which is inherently nonlinear and unstable system.The proposal is to deploy discrete optimal pole-zero approximation method for realization of digital fractional order controller.An approach of phase shaping by slope cancellation of asymptotic phase plots for zeros and poles within given bandwidth is explored.The controller parameters are tuned using dynamic particle swarm optimization(d PSO)technique.Effectiveness of the proposed control scheme is verified by simulation and experimental results.The performance of realized digital FO-PID controller has been compared with that of the integer order PID controllers.It is observed that effort required in fractional order control is smaller as compared with its integer counterpart for obtaining the same system performance.

Solar Energy System with Digital Controller for Grid Connected Systems

--The solar photovoltaic （PV） module output voltage changes according to the variation of light intensity and temperature. This paper presents the implementation of an automatic digital controller of a DC-DC boost converter without batteries for a solar cell module by using a peripheral interface controller, which forms a closed loop, to control the ON-OFF period of the switching pulse. The output of DC-DC converter is maintained by automatically increasing or decreasing the pulse width. To produce the pulse width modulation （PWM）, the microcontroller is programmed according to the required duty cycle for the power switch. The PWM ON period is increased with the decrease in the PV voltage and vice-versa. The input voltage to the inverter is maintained constantly and is converted into an AC signal by using the metal-oxide-semiconductor field effect transistor （MOSFET） H-bridge operated in the sinusoidal pulse width modulation mode by using a PIC （peripheral interface controller） microcontroller. The generated AC signal can be connected to the AC grid or to the AC load. The simulated results by using Proteus 8 and hardware implemented results verify the effectiveness of the proposed controller.

Simulation and experimental research of digital valve control servo system based on CMAC-PID control method

Digital valve control servo system is studied in this paper. In order to solve the system problems of poor control precision and slow response time,a CMAC-PID( cerebellar model articulation controller-PID) compound control method is proposed. This compound controller consists of two components: one is a traditional PID for the feedback control to guarantee stability of the system; the other is the CMAC control algorithm to form a feed-forward control for achieving high control precision and short response time of the controlled plant. Then the CMAC-PID compound control method is used in the digital valve control servo system to improve its control performance. Through simulation and experiment,the proposed CMAC-PID compound control method is superior to the traditional PID control for enhancing stability and robustness,and thus this compound control can be used as a new control strategy for the digital valve control servo system.

Application study of digital PID controller in cockpit temperature auto-regulating system

Aiming at the inherent blemish existi ng currently in airplane cockpit temperature regulating system,a digital temperatu re auto-regulating design scheme of the system is put forward,namely,a digita l proportional-integral-derivative(PID) controller used for temperature contr ol is designed.And then it is applied in airpl ane cockpit temperature regulating system by adopting the way of cascade control.Experiment results indicate that the design scheme is reasonable and practical.

INTELLIGENT CONTROL SYSTEM OF PULSED MAG WELDING INVERTER BASED ON DIGITAL SIGNAL PROCESSOR

A fuzzy logic intelligent control system of pulsed MAG welding inverter based on digital signal processor （DSP） is proposed to obtain the consistency of arc length in pulsed MAG welding. The proposed control system combines the merits of intelligent control with DSP digital control. The fuzzy logic intelligent control system designed is a typical two-input-single-output structure, and regards the error and the change in error of peak arc voltage as two inputs and the background time as single output. The fuzzy logic intelligent control system is realized in a look-up table （LUT） method by using MATLAB based fuzzy logic toolbox, and the implement of LUT method based on DSP is also discussed. The pulsed MAG welding experimental results demonstrate that the developed fuzzy logic intelligent control system based on DSP has strong arc length controlling ability to accomplish the stable pulsed MAG welding process and controls pulsed MAG welding inverter digitally and intelligently.

Digital close loop control system for current-programmed mode arc welding inverter

A small-signal model of current programmed mode pulse width modulation converter including the equivalent sampling effect is introduced and analyzed. In this model, an addition pole is brought out by the sampling effect in the current loop gain, and it affects dynamic bandwidth and stability of the inner current loop. By selecting the appropriate stability parameter which determines the additional pole and describes the degree of peaking in closed loop transfer function, a control model of current programmed full bridge arc welding inverter with maximum frequency bandwidth and stability can be obtained. Small and large amplitude pulse current outputs are employed in simulations and experiments and results validate the design method.

Network Reliability Analysis of Digital Instrument and Control System with GO-FLOW Methodology

In this paper,the network reliability of an actual digital instrument and control system (DICS) network is analyzed by using GO-FLOW methodology (GFM).The evaluations of common-cause failure (CCF) and uncertainty are incorporated.Three significant CCF groups (real time servers,gateways,reactor protection system) and three typical time intervals (10 min,1 h,and 24 h) are selected in the analysis.It is concluded that the network contribution of CCF accounts for over 68% of the system failure probability.The result indicates that GFM is suitable for the network reliability analysis.

APPLICATION OF IMPROVED PRODUCTION ACTIVITY CONTROL ARCHITECTURE FOR SHOP FLOOR INFORMATION SYSTEM IN DIGITAL MANUFACTURING

Shop floor control （SFC） is responsible for the coordination and control of the manufacturing physical and information flow within the shop floor in the manufacturing system. Weaknesses of the production activity control （PAC） architecture of the shop floor are addressed by the Maglica＇s new system architecture. This architecture gives rise to unlimited number of movers and producers thus evolving more complex but decentralized architecture. Beijing Institute of Technology - production activity control （BIT-PAC） architecture introduces an idea of sub-producars and sub-movers thus reducing the complexity of the architecture. All the equipments including sub-producars and sub-movers are considered to be passive in the proposed shop floor information system. The dissemination of information from sub-producers and sub-movers is done manually through a PC. Proposed BIT-PAC SFC architecture facilitates the information flow from shop floor to the other area of the organization. Effective use of interact information services （IIS） and SQL2000 is done along with the ASP.NET technology to implement the application logic. Applicability of the software based on BIT-PAC architecture is checked by running application software on a network PC that supports the dynamic flow of information from sub-producers and sub-movers to the other parts of the organization. Use of software is also shown at the end for BIT training workshop thus supporting the use of SFC architecture for similar kind of environments.

Real Time Implementation of Series Expansion Based Digital Controller for Magnetic Levitation System

This paper addresses a digital controller for a real time magnetic levitation system using series expansion of pulse transfer function, which achieves desired closed loop response. The proposed digital controller designed, based on series expansion of pulse transfer function by solving a linear equation using the method of least squares, which improves the transient performance and step tracking capability of the compensated system. The designed algorithm used for the control input is not iterative, so the calculation is very fast. The proposed control scheme has successfully applied on maglev system and also validated through the simulation and hardware experimental results.

Digital Instrumentation and Control System for Unit 5 ＆ 6 of YangJiang NPP

The article describes the digital instrumentation and control system for unit 5 ＆ 6 of YangJiang NPP, involving the overall I ＆ C （instrumentation and control） structure, the basic requirements and independent verification and validation. Advanced I ＆ C systems for YangJiang NPPs have to meet increasing demands for safety and availability. Additionally, the specific requirements coming from the nuclear qualification have to be fulfilled.

THE FEEDBACK DELAY IN DIGITAL CONTROL

It is a fact that the feedback delay actually arises in digital control systems. It is necessary to modify the structure of digital control systems and develop new control algorithms, which is done in this paper. A great number of digital computer simulation experiments have shown the obvious advantage of the new algorithms.

Simple Push-Type Wave Generating Method Using Digital Rotary Valve Control

The important parameters to describe waves are their amplitude and length.In order to make it easier to improve wave amplitude and facilitate wave experiment,a simple push-type wave generating method using digital rotary valve control was proposed and different wave amplitudes were generated by the new method.After the mathematical model of the new method had been established,numerical analysis based on the linear wave theory was carried out by means of Matlab/Simulink software tools,and experiments were conducted on the push-type wave maker to ascertain the validity of the established model and the numerical simulation results.It shows that both experimental and theoretical results agree relatively well,and the plate motion frequency and amplitude of the push-type wave maker can be continuously adjusted and the various required regular waves can be obtained.Although the wave amplitude and length descends with the increasing of working frequency,the wave amplitude can be improved conveniently by setting the axial opening width of the valve and the oil supply pressure of system.The wave length remains unchanged with the axial opening width and the oil supply pressure change.The research indicates that different regular waves can be easily generated by the new method and the wave amplitude can be further improved in a certain plate motion frequency range.

Digital Servo Control of a Robotic Excavator

An electro-hydraulic control system is designed and implemented for a robotic excavator known as the Lancaster University Computerised and Intelligent Excavator （LUCIE）. The excavator is being developed to autonomously dig trenches without human intervention. Since the behavior of the excavator arm is dominated by the nonlinear dynamics of the hydraulic actuators and by the large and unpredictable external disturbances when digging, it is difficult to provide adequate accurate, quick and smooth movement under traditional control methodology, e.g., PI/PID, which is comparable with that of an average human operator. The data-based dynamic models are developed utilizing the simplified refined instrumental variable （SRIV） identification algorithm to precisely describe the nonlinear dynamical behaviour of the electro-hydraulic actuation system. Based on data-based model and proportional-integral-plus （PIP） methodology, which is a non-minimal state space method of control system design based on the true digital control （TDC） system design philosophy, a novel control system is introduced to drive the excavator arm accurately, quickly and smoothly along the desired path. The performance of simulation and field tests which drive the bucket along straight lines both demonstrate the feasibility and validity of the proposed control scheme.