The outlook for computer control

Control system simulation — computer control

DC motors are known for simple design and consistency are used for control area section of the industry. In many variable speed systems, it is commonly used where wide speed ranges are required. The conventional controller is not compatible with computer controller. To overcome the short falling faced with conventional controller, a simple discrete PID controller designed for the speed control of DC motor. Advantage of discrete controller simple in its design and easily interface with computer system to access the control action. The dynamics of the system is calculated and controller parameters are obtained by root locus method. This research paper emphasizes the design of a simple digital control system that combines a discrete Proportional Integral Derivative (PID) controller with Direct current (DC) motor. The complete simulation is carried out with MATLAB / SIMULINK software.

Computer control in the process industries: By Brian Roffel and Patrick Chinn. Lewis Publishers, Leigh-on-Sea, 257 pp., #54.75

Part 1 Computers in control systems: historical development digital computer interfacing structure of a digital control loop interface units data representation and aliasing. Part 2 The z-transformation: definition of the z-transform z-transform properties inverse z-transform pulse of z-transfer functions of systems discrete approximations numerical integration pole-zero mapping modified z-transform multi-rate sampling systems analysis of multi-rate systems fast-slow multi-rate systems closed-loop multi-rate systems. Part 3 Analysis of sampled-data control systems z-transformation of systems stability in discrete systems time domain analysis root locus analysis frequency domain analysis. Part 4 Digital compensator design: continuous domain design digital design digital root locas design state feedback design digital PID control disign deadbeat response design optimal control design controller design in the presence of noise. Part 5 Real-time computer control systems: hardware requirements the digital computer and peripheral equipment the real-time clock interface units software aspects controller implementation programming languages system design co-ordination sampling rate selection and quantization errors computer/device communications interrupt handling multi-tasking and background/foreground. Part 6 Advances in computer control: artificial intelligence expert systems examples of expert systems knowledge based systems in control engineering conventional controller design methods manual control methods fuzzy sets and rule-based control basic fuzzy operations fuzzy relations fuzzy control algorithms parallel processing techniques parallel computers algorithms for parallel (MIMD) computers programming parallel computers performance of parallel computers parallel processing in control engineering matrix algebra numerical integration fault tolerance. Appendices: Table of laplace and z-transforms continuous second-order systems response specifications frequency response characteristics the transputer and occam occam overview transputer systems and occam configuration vibration control of a flexible cantilever system simulation modelling and state estimation controller design user interface solutions.

This paper addresses the development of advanced computer control strategies and those applications in the thermal processes of metal industry. The process modelling involves the development of dynamic mathematic models with state space forms describing the thermal state in the heated and/or cooled objects. Dynamic model based optimal control strategies for both batch and continuous thermal processes in terms of the maximum principle, dynamic programming, heuristic search, etc. are also proposed in this study. The target of the development of optimal control for the heating processes is to provide the optimal heating patterns based on the given criteria and constraints associated with dynamic models and others. A complete hierarchical computer control structure for heating processes is also proposed. Finally, the application results of the proposed modern control strategies to a production scale slab reheating furnace are given.

Modern computer controlled radiotherapy treatment equipment offers the possibility of delivering complex, multiple field treatments with minimal operator intervention, thus making multiple field conformal therapy practical. Conventional quality control programs are inadequate for this new technology, so new quality control procedures are needed. A reasonably fast, sensitive, and complete daily quality control program has been developed in our clinic that includes nearly automated mechanical as well as dosimetric tests. Automated delivery of these quality control fields is performed by the control system of the MM50 racetrack microtron, directed by the CCRS sequence processor [D. L. McShan and B. A. Fraass, Proceedings of the XIth International Conference on the use of computers in Radiation Therapy, 20-24 March 1994, Manchester, U.K. (North Western Medical Physics Department, Manchester, U.K., 1994), pp. 210-211], which controls the treatment process. The mechanical tests involve multiple irradiations of a single film to check the accuracy and reproducibility of the computer controlled setup of gantry and collimator angles, table orientation, collimator jaws, and multileaf collimator shape. The dosimetric tests, which involve multiple irradiations of an array of ionization chambers in a commercial dose detector (Keithly model 90100 Tracker System) rigidly attached to the head of the treatment gantry, check the output and symmetry of the treatment unit as a function of gantry and collimator angle and other parameters. For each of the dosimetric tests, readings from the five ionization chambers are automatically read out, stored, and analyzed by the computer, along with the geometric parameters of the treatment unit for that beam.(ABSTRACT TRUNCATED AT 250 WORDS)

REMOVING BARRIERS TO THE APPLICATION OF AUTOMATION IN DISCRETE PART BATCH MANUFACTURING

Chapter 2 - Chemical Engineering — the First 100 Years

Nowadays, most of the works are based on electric vehicle usage for sustainable transportation using traditional energy storage device, such as battery. Usage of batteries in electric vehicles is having several disadvantages, for example, life span, temperature, and charge estimation. In this paper, a novel control scheme for battery and supercapacitor‐ (SC‐) based hybrid energy storage system (HESS) using hybrid proportional and integral‐ (PI‐) sliding mode control (SMC) for electric vehicle (EV) applications is introduced and implemented. This HESS with hybrid controller proves the usage of batteries in EVs to its fullest potential. The conventional control strategy for HESS follows two‐loop voltage and current PI controllers with low‐pass filter (LPF) and involves tuning of multiple control parameters with variations of source and load disturbances. Performance of the system is affected by tuning PI controller constants. A slow response time with linear PI controllers is long which is not advisable for starting and sudden jerk conditions of EVs. Moreover, the PI controller performance is affected by the system parameter variations during load changes. And these parameters are dynamic in nature due to nonideal conditions. In this paper, a hybrid PI‐sliding mode controller (SMC) scheme is designed to control the bidirectional DC‐DC converters to overcome the drawbacks of aforementioned issues. The combined PI‐SMC controller reduces the tuning effort and reduces the effect of shift in operating point in controller performance. Linear modeling is done using small signal analysis for each subsystems. Permanent magnet synchronous machine (PMSM) is used as electric vehicle. The entire system and its controllers are simulated using MATLAB‐Simulink, and detailed comparison is carried between conventional PI and proposed hybrid PI‐SMC scheme to regulate the DC link voltage. The results are tabulated and show that the hybrid PI‐SMC scheme outperforms in transient and steady‐state conditions than the traditional PI controller. A scaled hardware prototype of 48 W set‐up is developed using dSPACE‐1104, and the experimental results have been carried out to verify the proposed system’s feasibility.

Process of controlling pressure in process industries becomes difficult when the conventional controller is used because of not capable of handling delay time, rise time and steady-state error. So, in this work, the method of the combining the conventional controller with the optimised hybrid system is considered. In this hybrid system the combination of fuzzy logic controller and PID controller is taken for evaluation and performance analysis over the pressure process. Generally fuzzy controllers use a rule base to describe relationships between the variables that are used in the processes. The performance analysis is done for different conventional controllers like PID and fuzzy PID. The performance analysis for the controllers is based in considering conventional resultant parameters like rise time, peak overshoot and settling time. We proposed a hybrid fuzzy PID controller which utilises the properties and advantage of the fuzzy and PID controllers. The effectiveness of the Hybrid fuzzy PID controller designed is demonstrated in pressure process.

Control and Management of Wastewater Treatment Plants

Past research on wearable computers for maintenance applications has focused on developing displays and presentation formats. This study emphasized wearable computer control technologies. Alternative control technologies were compared with standard and voice controls. Twelve subjects performed a synthetic maintenance task using three control device combinations for three different types of input. Time and error data were collected. The results show that for pointer movement, standard controls took significantly longer than voice. For discrete input, standard controls required significantly more time than voice and alternative controls. However, there were no significant time differences among controllers for text entry fill-in. Error results showed no significant differences. This research suggests that alternative and voice controls provide similar performance levels and both are superior to standard controls. In environments with changing noise spectra and noise levels such as a flight line, the alternative control suite provides hands-free control that complements voice without sacrificing performance.

The field of application of electric resistance welded (ERW) tubes continues to expand these days, and the quality requirements are becoming more sophisticated from year to year. In order to meet these market conditions, more advanced technology for forming and welding is essential to ERW tube production, in addition to improvement of the quality of materials. Heat input control in welding especially plays a very important role in advancing and stabilizing the quality of ERW tubes. Various engineering processes related to heat control have been studied and developed. From the manual control in early days through PID feedback control to joint feedforward and feedback control based on computerized mathematical models — this sums up the development of heat control to this day. Mill lines today, however, must turn out a greater variety of ERW tubes of superior quality. The heat control functions and performance required for this purpose have been increasingly difficult to come by with the conventional computer control.

The internal model control (IMC) scheme has been widely applied in the field of process control. This is due to its simple and straightforward controller design procedure as well as its good disturbance rejection capabilities and robustness properties. So far, IMC has been mainly applied to linear processes. This paper discusses the extension of the IMC scheme to nonlinear processes based on local linear models where the properties of the linear design procedures can be exploited directly. The resulting controllers are comparable to gain-scheduled PI or PID controllers which are the standard controllers in process industry. In practice, the tuning of conventional PI or PID controllers can be very time-consuming. In this paper, the design effort of the nonlinear IMC and conventional controller design methods are discussed and the control results are compared by applying it to a Hammerstein process and nonlinear temperature control of a heat exchanger.

Enterprises in today's globalized world are compelled to react on threats and opportunities in a highly flexible manner. Hence, companies that are able to analyze the current state of their business processes, forecast their most optimal progresses and with this proactively control them will have a decisive competitive advantage. Technological progress in sensor technology has boosted real-time situation awareness, especially in manufacturing operations. The paper at hands examines, based on a case study stemming from the steel manufacturing industry, which production-related data is collectable using state of the art sensors forming a basis for a detailed situation awareness and for deriving accurate forecasts. However, analyses of this data point out that dedicated big data analytics approaches are required to utilize the full potential out of it. By proposing an architecture for predictive process planning and control systems, the paper intends to form a working and discussion basis for further research and implementation efforts in big data analytics.