Analysis and design of a digital actuator

Includes bibliographical references (pages 63-64)The typical control system configuration consists of a controller, a controlled process (the plant) and a set of one or more feedback elements. The controller in practice, is customarily an electrical device while the plant is often made up of mechanical components and processes. The conversion from electrical to mechanical energy in such a system is made in an electro-mechanical transducer (the actuator).\ud Present technology finds the controller taking the form of a digital computer with digital-to-analog conversion between the controller and the actuator. However, recent advances in the design of actuators have made possible the use of actuators which utilize digital inputs, thus eliminating the necessity for D/A conversion.\ud This project discusses the use of digital actuators in the design of closed loop control systems. It is shown how linear models can be derived for such actuators, based on the necessary\ud functions which must be performed and the physical principles which govern the operation of the device.\ud A hybrid control system design is carried out in this project to illustrate the use of this type of actuator. The design is based on a sampled-data model of the system, and utilizes the graphical root-locus technique in the design of the discrete controller.\ud Aspects of hybrid control system design and analysis, such as quantization error, intersampling ripple and transient responses are discussed. Finally, conclusions and recommendations on the use of digital actuator in hybrid control systems have been included in the paper