EE2001: Control systems exist in numerous varieties, both in the type of applications and level of sophistication: Circuit analysis Course Work, NTU, Singapore

Liquid Level System 

Control systems exist in numerous varieties, both in the type of applications and level of sophistication. Since most systems are dynamic in nature, controlling or regulating against a set of desired parameters is important to ensure good performance and quality standards.

Dynamic control systems are mostly described by differential equations. A common type of dynamic system, the liquid level system is shown in the figure below.

The liquid level system controls the amount of water in the system. Liquid level systems are commonly found in the industries, such as the oil industry, agrotech industry, electronic industry and etc.

i– Performance analysis on the system and design a complete liquid level control system that is able to control the amount of water in the system based on the requirement below.

• The amount of water flows into the system via an input pipe and the inflow rate is controlled by a pump. The pump will control the inflow rate or how much water is input into the system.
• A discharge valve will control the outflow rate of liquid from the system via the outlet. This is to prevent overflow of water in the system.
• The pump can be adjustable to control the inflow rate of the water into the system and the discharge valve can be adjusted to control the outflow rate of the water from the system. Draw the complete liquid level system that you have designed by adding in the pump and discharge valve and other relevant parts, if applicable. Indicate clearly the dynamic changing variables involved in the system such as inflow rate, outflow rate, and any other changing variables in the system.

ii– Model the transfer function of your newly designed liquid level system in part (i). Show your steps clearly in modeling the transfer function. In the modeling of the transfer function, state your assumptions.

iii– Explain your rationale behind the modeling of the transfer function in (ii) and describe how you obtain the transfer function. State any assumption that you have made in your modeling process.