Aidan O'Dwyer

A SUMMARY OF PI AND PID CONTROLLER TUNING RULES FOR PROCESSES WITH TIME DELAY. PART 1: PI CONTROLLER TUNING RULES.

Abstract The ability of proportional integral (PI) and proportional integral derivative (PID) controllers to compensate many practical industrial processes has led to their wide acceptance in industrial applications. The requirement to choose either two or three controller parameters is perhaps most easily done using tuning rules. A summary of tuning rules for the PID control of single input, single output (SISO) processes with time delay is provided in this paper.

PID compensation of time delayed processes 1998-2002: a survey

A time delay may be defined as the time interval between the start of an event at one point in a system and its resulting action at another point in the system. Delays are also known as transport lags or dead times; they arise in physical, chemical, biological and economic systems, as well as in the process of measurement and computation. Methods for the compensation of time delayed processes may be broadly divided into proportional integral derivative (PID) based controllers, in which the controller parameters are adapted to the controller structure, and structurally optimised controllers, in which the controller structure and parameters are adapted optimally to the structure and parameters of the process model. The purpose of this paper is to extract the essence of the developments in design, tuning and implementation of PID controllers for delayed processes over the five years 1998-2002, concentrating on journal publications. The paper will provide a framework against which the literature may be viewed.

Learning and Assessment of Student Communication Skills on Engineering Programs: Some Experiences

In this contribution, the author reports on, reflects on and evaluates case studies in which the ability to communicate effectively was embedded into modules for which the author had academic responsibility, on both Level 8 (Bachelors) and Level 9 (Masters) engineering programs. The generic competency was developed using formal student presentations, mostly done individually, with a minority done in teams. Peer and tutor assessment of the presentations was employed, following a structured guideline agreed with the students; among other advantages, peer assessment assists in the further development of student analytical skills and professional ethics. The contribution discusses the peer assessment experience, including formal student feedback on the process. The authors experiences are that the learning and assessment method is learner-centered, motivates independent learning, caters to a diverse student background and unlocks previous student work and learning experiences to the benefit of all learners.

Controlled breaking scheme for a wheeled walking aid

Abstract A wheeled walking aid with an embedded controlled braking system is described. The frame of the prototype is based on combining features of standard available wheeled walking aids. A braking scheme has been designed using hydraulic disc brakes to facilitate accurate and sensitive controlled stopping of the walker by the user, and if called upon, by automatic action. Braking force is modulated via a linear actuating stepping motor. A microcontroller is used for control of both stepper movement and for supervisory control. An encoder is used to supervise walker movement in terms of time, distance and speed.

Postgraduate student priorities in renewable energy research, as revealed through their development of dissertation project proposals

This contribution reports on, and reflects on, the teaching, learning and assessment of modules, on Level 9 (Masters) taught programmes in engineering, at Dublin Institute of Technology, whose outcome was the individual student development of a dissertation proposal. The modules were run, at various times, over the academic years from 2008-2013 inclusive. The modules are generic, and a team approach was taken to module instruction. Students were assessed (at different stages during the module) by evaluation of a dissertation proposal planner document, a reflective PowerPoint presentation, and more recently, evaluation of student use of a dedicated collaborative website, in addition to the assessment of their dissertation proposal. The contribution reflects on the module experience, including the lessons learned. The priorities of highly educated students, with an interdisciplinary ethos, in renewable energy are reported.

Pre-, post- and delayed post-test evaluation of the conceptual understanding of direct current resistive electric circuits of cohorts of first year electrical engineering students

There is an increasing diversity of educational background of students entering ordinary degree (Level 7) and honours degree (Level 8) programmes in engineering at Dublin Institute of Technology (DIT). Partly as a result, student reasoning about basic electricity concepts often differs from accepted explanations. The paper reports, analyses and reflects on the results of a multiple-choice diagnostic test to assess student understanding of such concepts (developed for U.S. high school and college students [1]) taken, as a pre-test, by four cohorts of first year students, on the same DIT Level 7 engineering programme, from 2008-12 (n=106) and two cohorts of first year students, on the same DIT Level 8 engineering programme, from 2010-12 (n=64). The performance of the student cohorts is similar, and is little influenced by previous exposure to relevant subjects in second level (high school) education. In the 2012-13 academic year, an updated version of the diagnostic test was taken, in a pilot study, by one cohort of first year students on the DIT Level 8 engineering programme; this test was administered as a pre-test before instruction, as a post-test immediately after instruction and as a delayed post-test approximately fifteen weeks after instruction. Results show that there is little improvement in conceptual understanding of d.c. resistive electric circuits, as measured by the test, when pre-test, post-test and delayed post-test scores are compared.

A Teaching Practice Review of the Use of Multiple-Choice Questions for Formative and Summative Assessment of Student Work on Advanced Undergraduate and Postgraduate Modules in Engineering

This paper reflects on, reports on and evaluates the use of multiple-choice questions, in both formative and summative assessment modes, on control engineering modules taken by advanced undergraduate and postgraduate engineering students, over four academic years. The material covered by the modules is analytical in nature. The rationale for examining the assessment strategy was the poor performance by students in a closed book traditional terminal examination on one of the advanced undergraduate modules over some years. The change in assessment strategy has improved student learning, as measured by assessment data; student feedback on the assessment methods is broadly positive. The assessment approach has been extended with success to some postgraduate modules. Overall, an evidence based approach is taken in the reporting and analysis.

An approach to teaching PID controller tuning

Abstract This paper discusses an approach to the teaching of PID controller tuning methods to students in control engineering at Dublin Institute of Technology. The method involves analytically calculating the gain margin, phase margin and maximum sensitivity for PI and PID controlled systems whose process is modelled in first order lag plus time delay (FOLPD) form. Students can examine the performance of many tuning rules from graphical results, allowing insight to be developed as to the most rational choice of the tuning rule for the application. Some preliminary work done to develop an expert system to allow a greater automation of the procedure for recommending a tuning rule, for user defined requirements, is also described.

The gain-scheduled control of a non-linear laboratory heating and ventilation process

This paper details the control of a pilot scale laboratory heating and ventilation system (VVS-400 product, Instrutek Ltd., Norway). The system is represented in 2×2 multi-input, multi-output (MIMO) form. A process reaction curve identification technique was used to model (in first order lag plus delay - FOLPD - form) the flow process and temperature process portions of the system, over a range of operating conditions. Tests revealed that both processes were continuously non-linear. A gain scheduler with static decoupling was designed, using look-up tables, to continuously interpolate for the most suitable PI/PID controller settings and decoupler gains. The contribution of this paper is the careful application, using well-known techniques, of a complete controller design cycle for a laboratory scale system.

Maintaining a balance at undergraduate degree level in the teaching of automation and classical control systems

www.instmc.org.uk 46 Advances in the past decade in the development and application of Programmable Logic Controllers (PLCs) and Automation Systems in both high technology industrial plants and in the more mainstream manufacturing sectors, has heightened the importance of ensuring that undergraduate degree programme syllabi are designed to adequately cater for the teaching and training of students in automation. Prior to this growth in automation, delivered syllabi in Control Systems on most Electrical Engineering programmes had a theoretical rigour, reflecting the mathematical nature of the topic. A major challenge currently facing departmental lecturing staff and programme coordinators is that of the design of balanced programmes in Control and Automation Systems, to adequately reflect the importance of both streams. Owing to the applied nature of automation systems, a move towards a more Problem Based Learning teaching methodology in delivery of modules would seem the preferable way forward. At the same time, design of a balanced programme will require inclusion of sufficiently indepth modules in classical control and process control, in order that graduates are provided with a good theoretical grounding in the subject, allied to practical hands-on experience in laboratory and project work. In summary, academic staff have the responsibility of providing the educational basis necessary to equip students with the skills required to cater for the needs of industry, while also providing a research arm for students who may wish to advance by way of postgraduate study to higher degrees. Dublin Institute of Technology is Ireland’s largest third level Institute, with different faculties located on sites throughout the city of Dublin. The Faculty of Engineering caters for up to 3,000 students with a full range of programmes including apprenticeship, certificates, diplomas, three-year ordinary degrees, four-year honours degrees (full-time), equivalent standard honours degrees (parttime), taught masters degrees, and funded research MPhil and PhD degrees. The Faculty contains five Schools: Control Systems and Electrical Engineering, Mechanical and Transport Engineering, Manufacturing Engineering, Electronic and Communications Engineering, and Civil and Building Services Engineering. An important and prided feature of DIT policy is that of its ladder system by which students may progress from apprenticeship and certificate programmes right through to MPhil and PhD degrees. Within the School of Control Systems and Electrical Engineering there are three departments: Control Engineering, Electrical Engineering and Electrical Services Engineering. The School has developed over several decades; its earlier focus was in preparing students for the examinations of the UK-based institutions, in particular the City and Guilds of London Institute and the Engineering Council. Currently, the school offers three undergraduate degrees in Electrical Engineering: (1) An ab-initio full-time three-year ordinary degree (Bachelor of Engineering Technology) with two main streams: Control and Automation Systems and Electrical Energy Systems. This degree is an upgrade and reformulation of a previous three-year diploma; it provides the education component for IEng registration and is thus comparable with a UK HNC/HND award, or equivalent. (2) An ab-initio full-time four-year honours degree (Batchelor of Engineering) with a modest level of specialisation in the following areas: Communications Engineering, Computer Engineering, Control Engineering and Power Systems Engineering. This degree is accredited by the Institute of Engineers of Ireland; it provides the education component for CEng registration and is thus comparable with a UK Bachelor of Engineering award at