Controllers for Marine Engineering Systems Essay - 1

Controllers for Marine Engineering Systems - Essay Example Time was calculated with that device by regulating the water level in a vessel and ascertaining the quantum of its flow out of it. (Australian Maritime College, department of maritime time engineering lecture notes on instrumentation and process control. (http://academic.amc.edu.au/hnguyen/IPC/IPC01-06.pdf, viewed on 23rd August , 2007) Development of instrumentation and control systems were very slowly till the Second World War. It progressed and accelerated with tremendous speed after the war. Initial progress was in single loop control systems. These contain a single feedback channel and this technology was elaborated since then for acquiring multi-loop systems In recent years marine vehicles are designed in swift progression. There are unmanned underwater vehicles, surface ships and high-speed crafts with integrated bridges. These marine vehicles and their engines are controlled with the aid of computer science. But designing and producing a computer-based automatic control system were challenging in marine control engineering till recently. Several types of control are used now. They are control applications in marine and offshore systems like CAMS (Control Applications in Marine Systems) and MCMC (Maneuvering and Control of Marine Crafts), maneuvering, control and ship positioning systems, robust and reliable control systems, optimization methods in marine systems and modeling, underwater vehicles and robotics, offshore systems, traffic guidance and control systems, fault tolerant control, detection and isolation in marine systems, engine and machinery control systems, machinery surveillance, condition monitoring and quality control systems, networking and IT for marine control. (http://academic.amc.edu.au/hnguyen/IPC/IPC01-06.pdf, page 1, viewed on 23rd August 2007). The history of automatic process control reveals that the PID controller heralded all the mechanical devices used in the marine engineering. Earlier these mechanical controllers used a lever, spring and a mass. Compressed air activated the system and 2 such pneumatic controllers were treated as the industry standard. Times have changed then and likewise the techniques. Proportional Integral Derivative, abbreviated to PID controller is a generic control loop feedback mechanism. It is extensively applied in industrial control systems. This controller rectifies errors occurred between a measured process variable and a set-point by calculating and outputting corrective action which could adjust the process. (http://en.wikipedia.org/wiki/PID_controller, viewed on 23rd August, 2007). The calculation is based on three elements viz., the Proportional, the Integral and Derivative values. The first one considers the reaction to the present error, while the second regulates the reaction on the sum of recent errors and the third determines the reaction to the rate of error change. The sum of these three is taken as output to a control element. By adjusting the proportional, the integral and the derivative values, the PID can give control action for specific requirements.