Modeling and Simulation of Electric Propulsion System of Unmanned Underwater Vehicles using MATLAB GUI

The Project aims at the innovation and development of Underwater Technologies for our country. As our country is surrounded by water but we lack the exploration of resources hidden under it. We look for developing an advanced and efficient UUV (Unmanned Underwater Vehicle) which will be propelled by

Project Title

Modeling and Simulation of Electric Propulsion System of Unmanned Underwater Vehicles using MATLAB GUI

Project Area of Specialization

Electrical/Electronic Engineering

Project Summary

The Project aims at the innovation and development of Underwater Technologies for our country. As our country is surrounded by water but we lack the exploration of resources hidden under it. We look for developing an advanced and efficient UUV (Unmanned Underwater Vehicle) which will be propelled by an Electric Propulsion System. Electric propulsion system (EPS), in which battery is the power source, electric motor is the fundamental driving element and propeller is the core driven equipment, is a very important concept for an energy efficient propulsion of underwater vehicles. The basic mathematical design of proposed EPS accumulates the vital abilities to be energy efficient, provide high initial torque along with high speed and enough endurance to acquire the desired target range. The simulations using MATLAB have been carried out to produce graphs between numerous operational and design variables. The simulations have further been integrated with the Graphical User Interface (GUI). A CAD design has also been proposed considering the shape and weight of the vehicle. A scaled-down prototype has also been developed to investigate and validate the obtained results and a hardware prototype will be developed to authenticate the variation of several operational parameters which variegate as the propeller of the vehicle rotates. The project focuses upon the Electric Propulsion assembled with Brushless DC Motor (BLDC Motor) which yields a much more efficient power transfer, together with high initial torque and overall top speed. The variations in parameters shown in graphs obtained through simulations are briefly discussed and compared with the work of previous researchers. The GUI will help to have a generic idea of the required output power ratings of motor and battery if some of the general specifications of UUV are known.

The methodology followed is;

• Conduct an analytical study to identify the design and operational parameters affecting the efficiency of UUV.
• Develop a mathematical model to describe the relationship among the design and operational parameters.
• Develop a simulation of Electric Propulsion System and map the results using MATLAB GUI.
• Develop a CAD design of the UUV keeping in view the placement of components to reduce the drag force.
• Develop a scaled-down prototype keeping in view the parameters of a high speed UUV.

Project Objectives

In this project, the model of an efficient propulsion system for UUVs, known as Electric Propulsion System, is proposed. The mathematical equations relating drag of the vehicle with several design and operational parameters have been discussed. The paper provides a fair estimation of power ratings of the propellant (motor) and the battery required for the propulsion of UUV, if targeted speed along with some basic dimensions of the body are known. The simulations using MATLAB provide thorough graphical understanding of mathematical relations. Further, the motor used in our case is BLDC, and the reason for its priority over the other machines has been tried to be showcased to a maximum possible limit within the frame of this project. The variation of drag with operational parameters as stated by mathematical equations has been compared with model and results obtained through MATLAB. The results clearly show that the drag increases as speed of vehicle is increased. The values of speed have been varied from 0.257 m/s (0.5 knots) to the ultimate speed goal of 7.716 m/s (15 knots). The plotted polynomial expresses that relation is somewhat exponential. The results are further validated by comparing them with previous work. This verifies the relation between drag and AUV speed. The proposed Electric System is going to be a cost-effective propelling solution for the UUVs developed in our country. By using the Simulator developed, any type of submerged or sub-sea vehicle can be designed. A few basic dimensions are needed and you have quite a fair estimation of the Electrical System of the vehicle. The proposed UUV will help Pakistan’s Naval Force to compete with rest of the Naval Forces in terms of modern usage of technology. The mathematical equations relating several design and operational parameters have been derived.  The derived equations provide a fair estimation of power ratings of motor and the battery required for propulsion. The simulation using MATLAB provides a fair graphical understanding of mathematical relations.  The integrated GUI puts in all the complex relations in a nutshell as we can observe all the necessary variations in fundamental parameters related to UUVs on a single screen. In the GUI window, length, diameter (basic design parameters), speed and mission’s duration of UUV are to be entered as inputs and the relations amongst several operational parameters can be observed in real-time.

Project Implementation Method

This project is implemented in underwater vehicles or any body which is electrically propelled and move underwater this propulsion system works for it. This system is very efficient and cost effective also this system has neglegible losses because no mechanical system is involved in it. The efficiency of motor which is the propellent of our system is 90% because we choose BLDC motor. Also this system can also be suitable with some modifications for the bodies which runs on the surface of water. This system is very compact and it's results are verified from Remus 100, Remus 600 and Tethys. These are the UUVs which are used by US Navy for low speed operations.

Benefits of the Project

Pakistan is one of those countries which has a very large coastal area and this ocean of Pakistan becomes more prominent due to the geographic location of Pakistan because Pakistan is the gateway to Central Asia. China is the largest economy of the world also interested in this and that’s why CPEC is established between Pakistan and China. Many other countries are also interested in this CPEC project. This shows that how much this Pakistan’s sea is important. But due to this importance the enemies of Pakistan also looking towards this sea and try to unstable Pakistan. Our project is designed specifically by keeping this in mind. This project is basically designed for military operations undersea. It helps Pakistan’s Naval force to compete with other marine forces in a very competitive and modern way rather than in a traditional way. Till now we are using the submarines even for surveillance which carries a number of sailors too. This directly affects our economy because a big size of submarine consumes a large amount of fuel also it is quite dangerous for the lives of crew members because submarine’s life is consider a very tough life. There is a very big point that as a developing country how can we expend a huge amount of money in terms of fuel just for surveillance operations. Now to cater out this thing we proposed unmanned underwater vehicles with electric propulsion system. The unmanned underwater vehicle increases the efficiency of our Navy in a way that it can easily perform any of the underwater operation without any human supervision. It is said to be a prototype or replica of submarine up to some extent. It can perform the surveillance operations easily and shows the real time data of sensors on ground station. Through unmanned underwater vehicles we can easily monitor our enemy continuously without any difficulty. One UUV can work of 12 to 16 sailors which reduces the man power. Also the electric propulsion system makes the unmanned underwater vehicles more efficient and cost effective. Since it is a pure electric system so it reduces the weight of UUV and no mechanical losses occurs in it. Also it good for the underwater atmosphere because any type of carbon emission does not takes place in this which is suitable for marine species.

On commercial scale these unmanned underwater vehicles are also impressive in searching mines and repairing of underwater pipeline in oil and gas sector. Rather than to setup a whole system for the location of oil or gas underwater these UUVs can be used as a alternative by just placing those detecting sensors on it.

So in a nutshell our project is to design a efficient and cost effective propulsion system for underwater vehicles on which different sensors can be placed and perform various operations that are discussed above.

Technical Details of Final Deliverable

The Electric Propulsion System is a pure electric system and consists of battery, motor and propeller. This losses in this system are negligible because we use BLDC Motor and it’s efficiency is approximately 90% also there is no mechanical losses in this system.

We design our system on following specs:

Length of UUV=1.733 meter

Diameter of UUV=0.255 meter

Pitch of propeller=7 inches (0.1772 meter)

Depth=100 meter

Speed ranges= 1knot – 15 knots (1 knot=0.5144 m/sec)

Before going to hardware first we developed a mathematical model and simulate it through MATLAB. Through this we get different results and then we verified our results with Remus 100, Remus 600 and Tethys. In our mathematical model first we calculate the drag force which is basically the opposition force acts on the frontal area of UUV when it moves in water. The greater the frontal are the more will be the drag. This drag force is basically dependent on the “Cd” coefficient of drag and speed of UUV. By increasing the speed of UUV, drag force also increases. Then we multiply this drag force with speed of UUV to calculate how much will the drag power be required. To move the UUV from standstill position this drag power must be overcome.

Then we find the speed of propeller which is dependent upon the pitch of propeller which is 7 inch in our case and speed of UUV and also contains the nautical miles factor of 1852. Now to reach out towards motor’s rpm we multiply the rpm of propeller with the gear ratio which we take 2:1 in terms of rpm because we need a high torque at start. This shows that the rpm of motor is double the rpm of propeller. Since now we have output power and output rpm so through P=Tw, we calculate the load torque  This is basically the load on the UUV that it needs to drive. After this we through P=VI, we calculated the electrical power that consumed by the motor from battery to run the UUV. This is whole power flow of our system.

Next we simulate these relations through MATLAB, where we used PI controller to control the speed of motor and we used a three phase BLDC motor. We placed oscillograms to analyze the graphs of stator voltage, stator current, rpm of motor, electromagnetic torque, output power, thrust of propeller and endurance of battery.

Now to watch the whole electrical system in one screen we developed a MATLAB GUI, which takes the input of basic parameters like the speed of UUV, length of UUV, diameter of UUV and operation time and then on the basis of that inputs it shows the graphs of current from battery, rpm of motor, electromagnetic torque, power output, thrust of propeller and endurance of battery. So on the basis of some basic inputs, our designed simulator gives the idea of whole electric system in one screen to design our own system.

By integration of these three components the electric propulsion system has been developed which successfully drives the UUV in water up to a depth of 100 meter which we selected.

These are the whole technical details of our final deliverable.

Final Deliverable of the Project

Hardware System

Core Industry

Security

Other Industries

Education , Petroleum , Energy , Others

Core Technology

Others

Other Technologies

Robotics, Shared Economy

Sustainable Development Goals

Decent Work and Economic Growth, Industry, Innovation and Infrastructure, Life Below Water

Required Resources

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