Introduction
Air-deployable Amphibious Vehicle (ADAV) system has gained substantial attention due to its suitability to be used in military, civil and societal mission. Development of this ADAV vehicle integrates many features. The ADVAC system and its subsystem are developed by considering aerodynamic, environmental and structural aspects. For windy conditions fluid dynamic analysis is performed to access effect and suitable design adjustment. A prototype is built and tested in water borne and flight modes. The designed vehicle has to meet all requirements of adversity missions.
The objective of this study is to enable the company develop an amphibious vehicle that will assist achieve the following:
- Enhance military operations in water and land
- Bulletproof
- Water leakage resistant
- When hit they are not damaged
- Carry large amount of military personnel
- Equipped with machine guns for operations
1.0 System overview and system requirements
System engineering is a technical method, design approach, operations, realization and retirement of systems (Banerjee, et al., 2016). A system is a collection of different elements that produce results as unity. The elements consist of hardware, software, policies, facilities and all that is required to give system results. Results obtained must include, quality of the system, behavior, function and performance. The value added to an institution depends on the contributions and relationship of independent entities of the system that are interconnected. This assists institutional management to make technical decisions as far as institution productivity is concern. To achieve physical, operational and functional performance in a given environment of a system.
System engineering is a science of developing a system capable of achieving certain requirements within a given period. They seek balanced and safe design to oppose conflict of interest. An engineer must develop instinct and skills to optimize overall design not favoring systems at the expense of the other.
The role and responsibility of a system engineer might vary from project depending on the complexity and size of the project and phase of the life cycle. The lead engineers in the system must ensure that the system fulfills the technical requirements and needs of the system and the right engineering approach is followed (Feng, et al., 2019). The system engineer also ensures that activities are well coordinated and monitored as executed by the technical team.
Air-deployable Amphibious Vehicle (ADAV) system is a commercial weapon producer. This commercial company is committed to provide products and services for a national defense industry. This development is aimed at providing complete systems that will solve difficulty of border defense. This Air-deployable Amphibious Vehicle (ADAV) system must meet certain key requirements of defense department to upgrade the defense force of a country. ADAV is an amphibious battle vehicle that must have 30 tons’ combat weight that combines mobility on water and land in a protected modern vehicle. This vehicle transports many soldiers and weapons. This Air-deployable Amphibious Vehicle can be expanded to enable it have technical adaptability to protection, command and armament systems. This vehicle can also carry equipment and assume a special purpose role.
Amphibious vehicle, is a vehicle for transporting cargo and passengers that operate in water and on land. The earliest amphibious vehicle used tracks or wheels on land but with watertight structures to navigate in water. Amphibious vehicles are capable for accompanying and transporting military forces inland. Two major types were noted during the second world war II where a landing vehicle and army sponsored appeared. The tractor resembled a tank and whereas the army sponsored moved on rubber tire and propelled when a float. Both vehicles were re-designated and the Amphibious vehicle remain stable in the 21st century. Many of these vehicles were sold and used by private companies.
- 1.1 Company description
In this section, the company understands the project requirements and their accuracy. The collaboration country has a unique environment with large continent, numerous islands, coastal areas, plenty marine resource, lakes and rivers. The country has a complex terrain and far from populated areas. All these factors in place makes it difficult for defense force for instance boarder army to complete their mission of boarder protection, secret mission, rescue mission and patrol. In future the same defense force will play an international collaborative role all over the world. This mission has similar requirement capability. The system designed is aimed at performing domestic and oversea urgent deployment. The company will take responsibility for design and manufacture of the Air-deployable Amphibious Vehicle (ADAV) system.
1.2 Requirements of Air-deployable Amphibious Vehicle
In this section the company considers environmental conditions, the defense department requirements and their functions. The Air-deployable Amphibious Vehicle must have capability to change from water operations to ground operations without pause. It must also be able to maneuver in automated task force and destroy other battle vehicles. Fighting weapons must have a range of engaging their targets. The speed of water has been identified as a top requirement. The following table shows the Air-deployable Amphibious Vehicle requirements that will enable the company understand the capability of the system:
| Environmental condition | Defense department Requirement of | Function |
| 1.Large landscape, complex terrain and unique environment 2. Distance from inhabited area3. Weather conditions such as thick fog, windy, and heavy rain. | Accurate placement Quick-response Security | Air deployable Low-altitude and high attitude deployable by aircraft. |
| Marine resources | Reliable capability ofAmbitious and costal landing | Water Engine and Battle system Moving of water to Engine system |
| Battle rescue | Maneuvering | Vehicle, weapon and communication systems |
1.3 potential risks
This potential risks deals with risk rating for all requirements in the following three categories:
- Probability: this is a probability of an issue developing like water intrusion at the point of testing marine maneuverability.
- Criticality: this deals with major functionality of the system. It includes maneuverability, survivability, combat ability and airborne deploy.
- Detectability: how easy can a system detect arising issue while performing a certain function. Issues that can be detected include power shortage, oil leakage and maintenance.
Risks that hinder a company from achieving its objectives can be classified as internal or external threats. External threat is all about confidentiality of the system developed. System design and testing must be done in a confidential manner. Participants involved and confidentiality controls are the major points in this process. These risks include stealing of design secrets. A mechanism has to be put in place to counter this threats to ensure security of the system developed. Internal threats include financial risk. Development of Air-deployable Amphibious Vehicle (ADAV) is a big investment in terms of equipment and facilities that will make the company incur a high cost. To avoid this risk a company must have financial control team, good relationship with the funding cooperation, funding organizations and professional lawyers.
- 2.0 ADAV Vehicle Scope
ADVAC vehicle Scope has been divided into major tasks (requirements)
- i. Deployable Air:
Missions undertaken are unpredictable, therefore Air-deployable Amphibious Vehicle (ADAV) should be deployed in mission areas and long distances. Extreme weather is also a challenge in low-air altitude (GORTON, 2013). To counter these two modes are designed that will include batch deployable air. This system can be used to transport aircrafts.
The following are different operational and system deployed in ADAV vehicle system:
High altitude model
- Front parachute-designed for vehicle hauling
- Rear grip parachute – designed to unfold a parachute system
- Four steady parachute-designed to avoid parachute coalition during unfolding.
- Four key parachutes unfold- this is important to reduce speed.
BPS system- this system is built under the vehicle, contains airbag used to decrease impact force.
Parachute unlock-this is an unlocking system that unlocks a lock automatically at an instant of landing the parachute breaks away from the vehicle. This design prevents a vehicle from rolling due to strong force of wind.
Personal landing-if the parachute unlocks fails, unlock process can be done manually.
Low- altitude deployable
This part of system depends on main parachute and BPS system design.
- ii. Amphibious
This section looks at what is required to make a vehicle that ca transport passengers and cargo while operating in water and on land. These requirements include;
Land power system
Engine: on land the system uses two turbo as power unit and it can improve the vehicle’s acceleration.
Wheel modification: six big wheels are designed to improve capability of avoiding obstacles. This makes the system move effectively on complex surfaces such as stone and sand.
Renewable battery: there must be a solar battery backup to be used at battle mission.
Water system
Pump jet: this supports the system perform in battle environments like lake, offshore, costal and river. Water jets have smaller size of propeller that rotates at a higher speed when in superficial water.
Liquid suspension
This involves a pack up of Six wheels, Design of Speed boat and a vehicle like design board with a plate to ease waves (Terramechanics, 2012).
Surf zone
Power switch.
Wheels unfolds and the water jet movements support the power. When the six wheels are put down the engine operate to support the system.
- Functional decomposition
This is a method of analyzing reduces a complex process to assist the company examine individual elements. In this case a function is broken down into smaller processes which are easier to comprehend. Functional decomposition is used in business to facilitate management and understanding of complex processes. This process of decomposition is broken into several steps. These steps include;
- Find basic function: this is the general assignment the design is supposed to accomplish. A business organization must identify a function that captures overall need of design.
- List of necessary sub-functions: on the functional decomposition place those functions that must be performed before the general function. Do not choose functions that require other functions before the general one.
- List of next sub-functions: find close sub-functions and place them on a functioning decomposition diagram.
- Inspect the diagram: when the company is through with the diagram, it has to ensure that no function has been left out. In case there is one that has been left out fit it by drawing a line on the diagram to locate it.
In Air-deployable Amphibious Vehicle(ADAV), there is an integration of multirotor and hovercraft, co-axial propellers, a motor all devoted to the frame. Assembly of this system is reinforced by high density body (Maimun, et al., 2016). Provision for batteries, pay loads, sensor, flight controller, electronic accessories robotic arm all are maintained for stability. After landing co-axial propellers rotate at 900 using a motor, there is forward movement through use of propellers. Buoyance is achieved by cushioning effect produced by duct fan
Figure1: Amphibious Vehicle model
Performance and design requirements determine the mission profile in water locations. Profile mission has several missions, propelling water surfaces, landing and hovering on air. All these missions depend on operational need.
- 4.0 System Design
System design has many functionalities that are compliant, whose aerodynamics and structures perform intended purpose. This is shown in figure 2 below
Figure2: Amphibious Vehicle design strategy
Hovercraft Design
Hovercraft is a vehicle designed to travel through multiple terrains that include, muddy surfaces, water and land. Duct fan at the center cushions the vehicle by forcing cushion air between the water surface and skirt (Nakisa, et al., 2015.). Air pressure increased acts at the hull’s base. Propelling co-axial rotors makes the hovercraft achieve a forward motion. Selection of the skirt is important because it determines the lift of a vehicle. To design hovercraft, many parameters have to be taken into account. The table below shows a list of assumptions to be incorporated in performing design calculation.
| No | Empirical relation |
| 1 | Length to width |
| 2 | Bag pressure |
| 3 | Forward thrust |
| 4 | Propeller pitch |
| 5 | Vertical thrust |
Selection of Skirt Material
Skirt functionality to realize hovering must have enough tensile strength. Various survey on skirt materials reveal that nylon with urethane is a good choice for a tensile strength and has a resistance to characteristics of wear and tear.
Hull material
Hull is a material regarded as water tight to hovercraft and has support of many battery, payloads, and other systems developed electronically (Patents. & justia., 2020). It must withstand high pressure that comes as a result of cushion air during skirt inflation. Based on the survey polyurethane foam has a high strength.
Multicopter Design
Aluminum channel is considered for supporting the motors. Thrust and speed of motors are taken based on empirical relations.
Propulsion
Motors are selected based on the estimated speed and good motors endure a high battery capacity.
Battery selection
This depends on current consumption with discharge rate and sufficient voltage rate requirements.
Weight
The weight is estimated upon selection of materials.
- 5.0 Structural analysis
Multirotor configuration has horizontal and vertical frames made of aluminum because of its characteristic of light weight.co-axial propellers are attached at the horizontal frame. Hovercraft hull is used to anchor vertical frames. Propellers produce thrust that act on fixed horizontal support and vertical axial. The effect of loading is calculated using structural analysis. Displacement is experienced at horizontal frame ‘s tip. Other amphibious structure experience lower level.
Aerodynamic analysis
Aerodynamic evaluation is performed by varying wind speeds with different attack angles. Computational fluid analysis platform is used to scrutinize pressure and velocity during flight conditions and aerodynamic coefficients. Quality is evaluated by performing skewness and orthogonality characteristics (Anon., 2011). Pressure is considered to reduce buoyancy and wall inference. No heat and plane symmetry that perform simulations. Simulation results show that different angles to attack collision with frontal body and causes drop in velocity drop because of pressure stagnation. For different angles coefficient is estimated and calculated. Substantial drag reduces endurance as evident at the substantial drag. To reduce drag effect, configure the blended nose and front panel as required.
Water sample collection
A degree of freedom actuated by servo motor collects water samples. A water sacking pump is carried by end-effector which connects through a horse. Water is collected in storage tanks of one Liter capacity. Depth of water is controlled by use of a rope driven through a motor.
The robot arm is manipulator is made of carbon and water proof motor servo attached to it. Stability of a vehicle is assured by distributing water in a two way (Sellfy, 2020.). The sensor of the water level measures quantity and gives a response protect arm. Figure 3 shows payload which motivate servo motors. Feedback is given by use of pumps and water sensors in digital and analog form.
Fig 3: Main control unit
Ground control
This is a station that consists of a computer and payload, flight data and corresponding links. The vehicle mission is planned and the body streamed through video link. Once these filthy areas are identified a vehicle lands on water through hovercraft mode.
Fig 4: Ground control station
A typical fright computer control is shown in the figure below. It acts as a central hub where orientation, heading direction and position are controlled. At the same time data transmission, actuation of servos, battery monitoring and robotic arm take place.
Figure 5: Fright control
the figure below depicts the mission of airborne mode that explains radio frequency signals received and transmitted through a module. Received signals are sent modulated form by flight controller. Vehicles are navigated and controlled by fright controller computers during hovering and flying modes. Signals are sent to speed controllers to actuate brashness motor to navigate a vehicle in a given altitude and attitude (Su, et al., 2011.).
Fig 6: Born air mission.
Payload control actuates water pump, quality sensors and robotic arm to perform quality and analysis to samples (Anon., 2020.). This is shown in the figure below.
Fig7: Sampling mission.
Fabrication
ADAV was invented based on selected motors, battery, propellers, skirt and hull materials. Aluminum frames were mounted on the hull and Knut joints are used and a propeller mounted (WANG, et al., 2017). At the hull’s center a propeller is mounted to produce pressure that can lift a vehicle.
- 6.0 ADAV vehicle proposal
Company structure covers the following areas
- Introduction to Air-deployable Amphibious Vehicle (ADAV) system
- System engineering process
- System analysis and control
- Planning, organization and managing of ADAV system
Introduction to Air-deployable Amphibious Vehicle (ADAV) system
System engineering is process that integrates all fundamental requirements, functional allocation, design synthesis and all are balanced and controlled.
System engineering process
The system model is flexible to accommodate technology by varying maturities. Systems that depend on mature technologies proceed relatively quickly. This is in comparison to immature technologies that take long period to develop and produce.
System architecture involves associated products, physical architecture and services rendered.
System analysis and control
The purpose of system analysis is to enable a company make informed decision and select alternative solutions. This is effected by carrying out cost effective analysis to offer solutions at a relative cost.
Planning, organization and managing of ADAV system
This organizational planning establishes organizational structure that achieves engineering objective (WANG, et al., 2019). This includes event scheduling, control methods and feedback establishment. Planning should also establish estimated system funding and proper relationship between technical processes and acquisitions.
- 7.0 Conclusion
Amphibious vehicle is established to achieve mission endurance and carry payloads. Its design combines functionalities of hovercraft and multi-rotor. Performance of ADAV is measured in terms of stress, stagnation pressure, deformation and forward velocity to expected conditions. Right materials have to choose to obtain the strength characteristics, propeller and motor to obtain sufficient force and robotic arm used, prototype built is tested in many water body conditions to check its stability and response.
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