Control Systems Principles control systems teaching, modelling, experiments, design, simulation, ball and beam system, ball and hoop, servomechanism trainer, servo trainer, servo control systems, coupled tanks system, coupled electric drives, engine control systems

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Control Systems Teaching Equipment

At a time when many universities and colleges are using simulated systems to teach control, we strongly maintain our belief that designing and implementing a control system using real equipment is the only way to gain 'deep knowledge' about how real control systems operate. Simulation is an invaluable tool for professional engineers who are investigating how things work - we use them extensively on systems where we cannot access the real system - either because it has not yet been built or is in a place we can't go (e.g. the human brain when we model and simulate neurodegeneration). However, a student learning about control engineering is different from professional control systems engineers investigating system behaviour.
Running a simulation is not the same as learning with a real system, with all the quirks and features that happen in real-life systems. We need real equipment, because real-life systems behave in ways that cannot be learnt from a textbook or computer animations. These notes take you through some of the control system equipment designs that we developed for teaching practical control systems engineering over a thirty year period. The designs and underlying teaching concepts have been shown to be robust and reliable through years of testing in real-life.

IMPORTANT NOTICE: Until February 2015 Control Systems Principles had a long-term agreement which allowed TecQuipment Ltd to manufacture and distribute our designs. Following unfortunate management and ownership changes at TecQuipment, the manufacturing agreement which permitted them to make our equipment is now at an end. As a result, TecQuipment is no longer an approved manufacturer of our designs , nor do they have our permission to use the intellectual property associated with our control engineering equipment designs. It has been brought to our attention that while TecQuipment have ended their agreement with us, they are continuing to manufacture to our designs, to use our intellectual property, and to claim copyright on teaching and laboratory material written by our lead designer Prof P Wellstead. We have sought advice concerning TecQuipment's unprincipled behaviour and as a result of that advice, we reserve the right, at a time of our chosing, to pursue TecQuipment through appropriate channels for use of our orginal designs, concepts, intellectual property and teaching materials.

Now back to our systems. To find out more about the systems, read on...

servo system Servo Control Systems

The task of a servo-mechanism is to regulate the input to a drive system (often an electric motor with a gearbox) to control the speed or position of a variable load. There is often a strong inertial component to the load and this is represented for teaching purposes by a flywheel. The electrical servomechanism is one of the most widely used control systems, and its characteristics are typical of the problems of servo control and regulation. The servo trainer is a laboratory version of these problems and is used to introduce the basic techniques of velocity control, position control and nonlinear compensation. For design techniques it provides the classical framework for teaching frequency-domain compensation using minor loop feedback, and lead-lag compensation (also see the frequency response analysis white paper on the downloads page). In addition to classical control concepts, servo trainers are also an excellent way to introduce state space design methods (through velocity feedback) and more advanced techniques such as robust control and non-linear compensation. For a white paper on the servo trainer, click on the White Papers button below.

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Coupled Tanks Coupled Tanks System

A standard problem in the process industries is liquid level control, and since we introduced our original coupled tanks system design in 1975, it has become a classic laboratory teaching system - with many versions and variations now available. The coupled tanks system is important because it is simple to understand - all the system dynamics are visible and the control action and system response are easy to understand without using theory. As a teaching tool it covers the fundamental process control techniques of three-term control, proportional control and integral control. For a white paper on this topic and a tutorial white paper on three-term control please click on the White Papers button below.

         white papers

CE106 Ball and Beam System

Understanding instability, and designing stabilising controllers, are vital skills for control engineer. Unfortunately, unstable systems are difficult to control and some are potentially dangerous in the laboratory. Our version of the ball and beam system was designed to solve these issues and to give a safe and highly visual demonstration of an open loop unstable system. The ball and beam system is an elegant demonstration of how a feedback control system can stabilise an system that is hard to control manually and in open loop. It shows a control engineering situation where feedback is absolutely essential in order to maintain stability. The design methods that can be used for the ball and beam range from phase advance compensation, observer- based or state feedback, to robust control. For white papers on this topic click on the White Papers button below.

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Process Trainer Process Trainer

The process industries and infrastructure services are the biggest industrial users of control systems. Understanding what a process control system is, what the process control loops are, and how to control them, is a fundamental part of a process control engineer's 'know-how'. A process system that incorporates many of the basics required for learning about process systems, and how to control them, is the process trainer illustrated to the right. It consists of a sealed process vessel with facilities for: flow control, process volume control, plus temperature and pressure loops. Although all these process problems do not always appear together the opportunity to work on them in the same system is both interesting and challenging. For a white paper on this topic click on the White Papers button below.

         white papers

Speed Governor Engine Speed Control

The regulation of engine speed with a centrifugal governor was a landmark development in practical control. The practical problems involved in designing a stable engine speed regulator led one of the earliest and most famous papers written about control theory - On governors - and helped start a revolution in control and automation. The engine speed control system is a practical way to learn about engine regulation using dither signals, nonlinear control, cascade control and multi-loop control. For a white paper on this topic click on the White Papers button below.

         white papers

Ball and Hoop Ball and Hoop System

The ball and hoop system is a variation on the ball and beam. It uses the behaviour of a ball rolling inside a rotating hoop to demonstrate the control of oscillatory systems. We are proud of this because it elegantly demonstrates the way in which the poles and zeroes of a system determine how a system's dynamics behave. It illustrates advanced concepts in control - especially the use of feedback and root locus design to place poles and feedforward to place zeros in desired locations. In summary, a superb demonstration of how poles and zeros determine systems dynamics. At a practical level the system is an example of a non-minimum phase system in which both feed forward and feedback can be used for pole placement and zero placement. For a white paper on this topic click on the White Papers button below.

         white papers

Coupled Drives Coupled Drives System

The Coupled Drives system demonstrates the type of control system found in industrial material handling where the speed and tension in a tape, sheet, wire or metal strip must be regulated. It is based on tension and speed control in two drives (the feed drive and the take-up drive), with the control objective of regulation the speed and tension of the material at an intermediate workstation. Fron a control teaching perspective, it is an example of a multivariable system with two interacting variables - speed and tension - that must be controlled by the torques applied by the two drives. The system is an advanced laboratory teaching tool for topics such as non-interacting controller design and multivariable controllers. For a white paper on this topic click on the White Papers button below.

         white papers



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