Control in Transport and Dosing Devices with Time Delay - Method for Extracting Region of Absolute Stability

Abstract

In modern system of automatic control, either in its object, or in the control part of the system, there are usually certain areas of uneven dimensions through which is conducted the transport of mass or energy of most diverse fluids, solids, or signal,. Delivery of energy, momentum, movement of the working body from one place to another happens with some delay.To rule out the possibility of inaccuracies in the methods of analysis and synthesis of this kind of automatic control system, it is necessary to take into account the occurrence of this delay. Influence of delay phenomena is essential for proper qualitative and quantitative description of the various processes. Typical types of delays are: transportation, technological and information.Typical representatives of system with transport delay are objects of type conveyor for coal, machinery for the production of plastic (extruders )and drugs and other devices, where is carried out transport , dosage and storage of solids.The material (granulate to produce plastics, drugs, coal…) is removed from the tanks to bunker . The conveyor belt appears as an integral part of the unit of dosing devices. Cross-section A of the bunker was unchanged over the entire height of the bunker. The task of these devices for transporting and dosing is the quantity of material to be retained in the bunker at a constant value (h = const) and we will developed system of automatic control for this purpose.According to earlier developed method of D – composition for time delay system with proportional regulator, we can separate the region in three-dimensional space frequency ω(Hz), gain K=1/α and time delay constant (τ), so that adjustable parameters guarantee absolute stability of synthetized automatic control system.To simulate dynamic behavior of the developed system we will use MATLAB software package. From the transient curve we can observe stability of the system for different value of parameters (α,τ) picked up from separate region in parametric plane α-τ