Event-Based Sampling Algorithm for Setpoint Tracking Using a State-Feedback Controller

International audienceEvent-based control techniques are investigated for output reference tracking in the case of linear time-invariant systems. In event-based control, the controller remains at rest if the system is behaving according to some predefined conditions, the feedback loop being closed only when the system states violate these conditions. In this work a reference system, which consists in the continuously-controlled version of the system under study, is employed. Based on the difference between the state of the event-triggered system and that of the reference system, we define a Lyapunov-like function, and show that if we can keep this function confined to a certain region, the tracking error would also be bounded. The trespassing of this function outside of the desired region is used as an event-triggering condition

Self-Playing Labyrinth Game Using Camera and Industrial Control System

In this master’s thesis, an industrial control system together with a network camera and servo motors were used to automate a ball and plate labyrinth system. The two servo motors, each with its own servo drive, were connected by joint arms to the plate resting on two interconnected gimbal frames, one for each axis. A background subtraction-based ball position tracking algorithm was developed to measure the ball-position using the camera. The camera acted as a sensor node in a control network with a programmable logical controller used together with the servo drives to implement a cascaded PID control loop to control the ball position. The ball reference position could either be controlled with user input from a tablet device, or automatically to make the labyrinth self-playing. The resulting system was able to control the ball position through the labyrinth using the camera for position feedback

Symbolic energy estimation model with optimum start algorithm implementation

The drive to reduce carbon emissions and energy utilisation, directly associated with dwellings and to achieve a zero carbon home, suggests that the assessment of energy ratings will have an increasingly prioritised role in the built environment. Created by the Building Research Establishment (BRE), the Standard Assessment Procedure (SAP) is the UK Government’s recommended method of assessing the energy ratings of dwellings. This paper describes a new, simplified dynamic method (hence known as IDEAS – Inverse Dynamics based Energy Analysis and Simulation) of assessing the controllability of a building and its servicing systems. The IDEAS method produces results that are comparable to SAP. An Optimum Start algorithm is explored in this paper to allow heating systems of different responsiveness and size to be integrated into the IDEAS framework. Results suggest that this design approach could enhance the SAP Methodology by the addition of advanced systems controllability and dynamic values

Industrial automation and control in hazardous nuclear environments

textThis report discusses the design and implementation of an automated system for use in geometrically-constrained, hazardous glovebox environments. This system’s purpose is to reduce a hemispherical plutonium pit into smaller pieces that fit inside of a crucible. The size reduction of plutonium pits supports stockpile stewardship efforts by the United States Department of Energy. The automation of this process increases the safety of radiation workers by handling radioactive nuclear material. This decreases glovebox worker dose and exposure to tools, sharps, and fines. This effort examines the hardware and software framework developed to support the use of a Port Deployed Manipulator (PDM) for a contact task. This research effort uses a 7 Degree-of-Freedom (DOF) PDM and a micropunch to reduce hemispherical pit surrogates. Formulation of the material reduction execution algorithm involved addressing a variety of topics related to industrial automation: 1. Collision detection and object recognition based on user-specified parameters. 2. Joint torque monitoring 3. Online motion planning for contact tasks 4. Object-in-hand industrial manufacturing 5. Grasping and handling of nuclear material 6. Software compliance via robust nonlinear control methods A high-bandwidth collision detection algorithm involving joint torque monitoring was developed to increase robot safety during operation. The motion planning algorithm developed for this effort takes variable geometric properties to be used with a range of hemishells. The algorithm’s feasibility was validated on a hardware test bed in a laboratory setting. Hardware cold tests conclude that mechanical compliance is sufficient for task completion. However, software compliance would increase performance, ef- ficiency, and safety during task execution. Two different nonlinear force control laws (feedback linearization and sliding mode control) that minimize object shear forces were developed using a simplified material reduction simulation. It is recommended that glovebox automation research continue to increase worker safety throughout the DOE complex.Mechanical Engineerin

European White Book on Real-Time Power Hardware in the Loop Testing : DERlab Report No. R- 005.0

The European White Book on Real-Time-Powerhardware-in-the-Loop testing is intended to serve as a reference document on the future of testing of electrical power equipment, with specifi c focus on the emerging hardware-in-the-loop activities and application thereof within testing facilities and procedures. It will provide an outlook of how this powerful tool can be utilised to support the development, testing and validation of specifi cally DER equipment. It aims to report on international experience gained thus far and provides case studies on developments and specifi c technical issues, such as the hardware/software interface. This white book compliments the already existing series of DERlab European white books, covering topics such as grid-inverters and grid-connected storag

Implementation of a PID Controller for Building Automation

This master thesis project has been performed in cooperation with TAC, a building automation company in Malmö and the Department of Automatic Control at LTH. TAC has experienced problems for some time with their PID controllers. This master thesis has therefore investigated the use of PID control at TAC, the problems with the existing controllers. The thesis also describes a new PID controller that has been implemented at TAC. The issues treated in the thesis are not only technical but also deal with the processes within a company when changing a control algorithm. The non-technical issues are for instance how the force of habit affects the development and that backward compatibility must be ensured. The new algorithm that was decided on and implemented is of a parallel-positional form. This basic form of the PID algorithm is proven to be the best choice. From a control point of view the controller successfully controls the processes in TAC's area of business. The PID controllers at TAC are used to control HVAC (Heating Ventilation and Air Condition) systems. The conclusion that the new PID controller is successful is based on simulations as well as tests at a commercial system. The PID controller is described in detail in the thesis. Features of the controller like setpoint weighting is described, as well as a tracking signal that allows the controller to be forced to externally specified values. Other features that are described include an offset added during control without the integral part, bumpless transfer, a rate of change limiting mechanism and other necessary features to make the controller practically usable. An investigation concerning possible concepts that may be useful in a new application programming tool has been performed as a part of the master thesis. The concepts determined to suit TAC are incorporated in IEC 61131. The concepts discussed in detail are amongst others SFC, the use of processes-tasks, instantiation and inheritance

Event-based fractional order control

The present study provides a generalization of event-based control to the field of fractional calculus, combining the benefits brought by the two approaches into an industrial-suitable control strategy. During recent years, control applications based on fractional order differintegral operators have gained more popularity due to their proven superior performance when compared to classical, integer order, control strategies. However, the current industrial setting is not yet prepared to fully adapt to complex fractional order control implementations that require hefty computational resources; needing highly-efficient methods with minimum control effort. The solution to this particular problem lies in combining benefits of event-based control such as resource optimization and bandwidth allocation with the superior performance of fractional order control. Theoretical and implementation aspects are developed in order to provide a generalization of event-based control into the fractional calculus field. Different numerical examples validate the proposed methodology, providing a useful tool, especially for industrial applications where the event-based control is most needed. Several event-based fractional order implementation possibilities are explored, the final result being an event-based fractional order control methodology. (C) 2020 The Authors. Published by Elsevier B.V. on behalf of Cairo University

Developing graphical user interface for a model predicative controller in an ABB software environment

A project at ABB CRC in Västerås aims at investigating the use of an MPC algorithm as a control module in 800xA. For users to interact with such a controller, faceplates need to be designed. This report describes the process, and results of designing such faceplates using among other the ABB Graphics Builder application. The challenge with the design work was mainly to create new and unique components and layout that seem intuitive to the user and at the same time looks and works similar to existing standards. Most of the planned faceplates were created and are working as intended, although a few functions are left for future work