AEROSPACE SYSTEMS ENGINEERING TERM PROJECT

Transcription

1 MIDDLE EAST TECHNICAL UNIVERSITY - DEPARTMENT OF AEROSPACE ENGINEERING AEROSPACE SYSTEMS ENGINEERING TERM PROJECT PROJECT GROUP # 2 FINAL REPORT Version: 1.1 Date 1/06/2012

2 1. Introduction... 3 A. Project Purpose... 3 B. Members of Team System Description... 3 A. System Design Requirements... 3 A.1) Functional Requirements:... 3 A.2) Performance Requirements:... 5 A.3) Interface Requirements:... 6 A.4) Reliability Requirements:... 6 A.5) Safety Requirements:... 6 B. Physical Architecture of the System... 7 C. Functional Architecture of the System... 8 D. System Internal and External Interfaces System Requirements Verification Verification of Functional Requirements Verification of Performance Requirements Verification of Interface Requirements Verification of Reliability Requirements Verification of Safety Requirements System Test Plan List of References

3 1. Introduction A. Project Purpose On the 2 nd of March 2012, the first class of course AE442 Aerospace Systems Engineering started. During this one semester lasting course, the students were instructed do design and build a system according to certain requirements. These requirements were created by the requirement team. This report is written to inform the reader about team 2 s system design. B. Members of Team 1. Yıldız Burcu ATILGAN 2. Gökçin ÇINAR 3. Hilal DEVECİOĞLU 4. Derya Mete SAATCI 5. Roy Michiel WASSINK 2. System Description A. System Design Requirements The system design requirements are arranged by the Requirement Team and provided as follows: A.1) Functional Requirements: [FNCT-REQ-1] Something we can build. (Build Criteria) -Assembly of the aerial vehicle should be under 5 minutes. 3

4 [FNCT-REQ-2] Something that can fly. (Flying Criteria) -The aerial vehicle should fly at (at least) 2 mt altitude(above the human height). -The aerial vehicle should stay aloft at least 30 seconds in order to be regarded as a flying vehicle. [FNCT-REQ-3] Something that is easy. (Easiness Criteria) -Number of different kinds of parts to be used at the aerial vehicle should not exceed 10.(i.e. if 4 servo motors are used, this is counted as one kind. [FNCT-REQ-4] Something that is cheap. (Cheapness Criteria) The aircraft should not cost more than 250 TL. Each expenditure should be proved with a bill and a copy of the bills should be provided together with a balance sheet in the final report file. Use of cheap materials such as Depron, Balsa wood, fabric, carbon tubes, foam board instead of aluminium, plywood, etc. is highly encouraged due to cost considerations. Any materials/parts that the groups currently have should be used and those will not be considered in the cost calculation. Thus, use of pre- 4

5 used/pre-bought materials is highly encouraged. However, instead of their price the source of material should be written in the materials cost table. [FNCT-REQ-5] Something that is one of a kind. (One of kindness criteria) The aerial vehicle should include at least one specific trait that has not implemented on aerial vehicle industry in Turkey. (May be World?) A.2) Performance Requirements: [PERF-REQ-1] The aerial vehicle should weight below 4 kg if powered, below 1,5 kg if unpowered. Use of lightweight materials such as Depron, Balsa wood, fabric, carbon tubes, foam board instead of aluminium, plywood, etc. is highly encouraged due to weight considerations. [PERF-REQ-2] The aerial vehicle should carry a payload which weights at least 1/10 of its empty weight. For electric powered air vehicles the battery weight should also be considered in empty weight calculation. [PERF-REQ-3] The air vehicle may either be powered or unpowered. It may take off using its own energy, or the initial energy may be given by a operator or a launcher mechanism. 5

6 A.3) Interface Requirements: [INTRF-REQ-1] Control of aircraft by a human/autopilot must be available. A rope such as on a tethered balloon, a remote/radio controller, or an autopilot/on-board controller would be among some control method options. [INTRF-REQ-2] Aircraft control mechanism/method should be used at least for a safe mission and safe landing. Further control capability is up to the contractor s/designer s choice. A.4) Reliability Requirements: [RLBLTY-REQ-1] The aerial vehicle should be used at least 10 times without giving any kind of fault. [RLBLTY-REQ-2] The aerial vehicle should be fly at METU environment. A.5) Safety Requirements: [SFTY-REQ-1] The aerial vehicle should not pollute environment. [SFTY-REQ-2] The aerial vehicle should not injure a human when it is touched. 6

7 B. Physical Architecture of the System The physical architecture of the system has to involve the parts of the vehicle and the materials consumed throughout the manufacturing phase. The following is the physical architecture of the quadrotor system. QUADROTOR SYSTEM Consumables Power Unit Propulsion Unit Control Unit Structure Unit Adhesives Battery Electric Motors KK Control Board Base Tire-up Cables Propellers Receiver Wood Tape Screws Electronic Speed Controller Foam Screws Rubber tire RC Controller Electric cables Figure 1 Hierarchical diagram of physical architecture of Quadrotor system The above figure implies that the flying vehicle, which is a quadrotor, consists of 4 main subsystems that came together at the final assembly of the vehicle with the help of the Consumables listed. These 4 main subsystems are named as the Power, Propulsion, Control and Structure units. The figure clearly implies the elements that make each unit up; hence, at the final step, the quadrotor. 7

8 C. Functional Architecture of the System To have a better understanding the functional architecture of the system, IDEF0 diagrams are used, as shown below. Requirements Literature Survey Design Quadrotor Information and Documents Team Members Money and Permissions Build Quadrotor Built Vehicle Safety Issues, Requirements Team Members, Assistants, Friends, RC Shops Fly Quadrotor Landed on Vehicle Figure 2 IDEF0 Diagram of the project Pilot As it can be seen from the figure above, the IDEF0 diagram of the project is divided into three main parts: design, build and fly the quadrotor. First of all, the design process requires the results of a literature survey as input and converts them into useful information and documents by the team members under the control of requirements given by the Requirement Team. Secondly, the building process takes place by using the output of the first step as control. In this stage, team members and assistants take different parts. Using money and permissions, the built vehicle is manufactured. Finally, the built vehicle is flown by pilot under the control of safety issues and requirements, and then landed on. 8

9 The details of these three stages are further explained by using again the IDEF0 diagrams. Requirements Design Quadrotor Literature Survey Perform Conceptual Design Conceptual Design of Possible Configurations Requirements Team Members Perform Detailed Design Information and Documents Team Members Figure 3 IDEF0 Diagram of Design the Quadrotor Stage (Stage 1) The figure above shows the internal IDEF0 diagram of Design Quadrotor stage. This part of the project again divided into two parts: Performing the conceptual design and detailed design of the quadrotor. First, a literature survey is done among both academic researches and commercial products to have a extensive knowledge about multirotors, especially quadrotors. Then the results are compared and discuss to see the advantages and disadvantages of some important phonemenas. With the help of these results, conceptual design of possible configurations are made while taking the requirements as main limitations. Then, these configurations are further studied and eleminated into one useful configuration to satisfy the requiriments in the most suitable way. The detailed design of this configuration is done by the team members and documentation is made. This documentation consists of mainly sizing and 3D drawing of all parts of the quadrotor, as well as a components list information. 9

10 Information and Documents Build Quadrotor Money and Permissions Gather&Buy Manufacturing Parts and Tools Manufacturing Parts and Tools Information and Documents Team Members, Assistants, Friends, RC Shops Manufacture Quadrotor Built Vehicle Team Members Figure 4 IDEF0 Diagram of Build the Quadrotor Stage (Stage 2) Figure above shows the internal IDEF0 diagram of Build Quadrotor stage. This stage consists of two parts as gathering/ buying manufacturing parts and tools and manufacturing the quadrotor. In order not to excess the budget limit, some parts are borrowed from the department labs and friends. To use the ESCs, battery and foam, a permission is taken from some department assistants. The propellers, controller, gyros and receiver are borrowed from friends. The parts that the team cannot borrow (motors, cables and body parts) are bought from local RC model shops (Eren Hobby). Manufacturing tools in department s aerodynamics lab are also used. With these parts and tools, the manufacturing stage of the quadrotor is initiated. Team members manufactured and assembled the parts and finished the building stage with a built quadrotor. In all of these stages, information and documents from the design stage are used as controls. 10

11 Safety Issues, Requirements Fly Quadrotor Built Vehicle Take off Quadrotor Pilot Took-off Vehicle Safety Issues, Requirements Fly Quadrotor Flying Vehicle Safety Issues, Requirements Pilot Land on Quadrotor Landed on Vehicle Pilot Figure 5 IDEF0 Diagram of Fly the Quadrotor Stage (Stage 3) The final stage is the flying stage and consists of 3 inner stages as take off, fly and land the quadrotor. This whole flying process is performed by the pilot under the control of safety issues and requirements. The safety issues are considered to protect people from an event of crash. To successfully finish this stage, the pilot needs to take off the built vehicle and then make it fly for at least 30 seconds as it is stated in the requirements. After 30 seconds, the pilot lands on the quadrotor, and the flying stage is ended. D. System Internal and External Interfaces In order to explain the control parts internal and external interfaces are determined. As provided by the diagram the external interface is about the relation between the control board and the external parts which are electric motors which are connected to the board with ESCs (electronic speed control), rudder, throttle, elevator and aileron PWM connectors and remote controller. 11

12 Remote Controller Motor # 1 (ESC # 1) Rudder PWM Motor # 2 (ESC # 2) Throttle PWM Elevator PWM Aileron PWM KK Multicopter Control Board Motor # 3 (ESC # 3) Motor # 4 (ESC # 4) Figure 6 The diagram showing of system external interfaces The internal interface is the relations in the control board. The used controller KK Multicopter Control Board has three main parts internally which are yaw, roll and pitch gyros. With the help of gain adjustments, the system creates feedbacks. KK Multicopter Control Board Pitch Gyro Yaw Gyro Roll Gyro Pitch Gyro Gain Adjustment Yaw Gyro Gain Adjustment Roll Gyro Gain Adjustment Figure 7 The diagram showing of system internal interfaces 12

13 3. System Requirements Verification This section describes the verification for the system requirements which are functional, performance, interface, reliability, safety, product and documentation. 3.1 Verification of Functional Requirements [FNCT-REQ-1] The quadrotor that the team has built is already fully assembled and ready to be used any moment. The only assembling parts are the connector cables of battery to ESCs and ESCs to receiver. [FNCT-REQ-2] The quadrotor is able to fly over 2 m and regarding the theoretical calculations it is able to maintain its flight from 3 minutes up to 7 minutes. [FNCT-REQ-3] As can be seen from the physical architecture, the quadrotor consists of 10 parts; namely: battery, motors, propellers, control board, RC controller-receiver group, ESCs, connector cables, base plate, spars and foam. Here the consumables are omitted, since they are only on the vehicle to keep it together. Also, all of the parts are easily accessible. [FNCT-REQ-4] Including all the bought parts, total price of the vehicle is under 250 TL. [FNCT-REQ-5] The designed system is unique for the department. The configuration used and the materials are chosen as non-used before. 3.2 Verification of Performance Requirements [PERF-REQ-1] Since the vehicle in consideration is powered, for this case the weight limit is 3 kg. The total weight of the whole system is 900grams, which successfully fulfils this requirement. 13

14 [PERF-REQ-2] Required payload that the system must carry is one tenth of the total weight of vehicle which is 900/10=90 grams. Carried payload of the build system is 100 grams. Therefore, it is above the level of required one. [PERF-REQ-3] The system is powered by the electric motors. With the full charged battery the vehicle takes off by the given throttle from the remote controller from the ground. 3.3 Verification of Interface Requirements [INTRF-REQ-1] The designed system is controlled by a remote controller conducted to a control board system called KK Multicopter Controller. [INTRF-REQ-2] With the inserted control board, the build system can fly to a certain altitude and then with the help of the landing gears made of foams the system lands safely. 3.4 Verification of Reliability Requirements [RLBLTY-REQ-1] The parts of the system are made as portable. In order to use it again, the parts can be ported safely and also if one of the electronic part gives an error, it can be changed. Also, the base configuration is made as portable. If wanted the parts can be unplugged; therefore, the system can be sheltered safely and be used again. [RLBLTY-REQ-2] The flight tests are done at METU environment. Furthermore, the demos will be done at METU. 14

15 3.5 Verification of Safety Requirements [SFTY-REQ-1] The system uses electric as a power source which is thought to be non-polluting environment. Moreover, none of the parts is using chemical reactions and while the system is working it does not leave anything dangerous (polluting) to the air or ground. [SFTY-REQ-2] The system does not have any sharp corners. In order to prevent the harm of possible crashes foams are placed on each of the corners. The main body is made of wood which is also harmless. The electric cables and circuits are covered to also prevent possible harm of electricity although the working amperes are small and nearly harmless. 4. System Test Plan Electronics and Propulsion Parts Test Intruments Test Indicators ESC Battery and receiver Signal detected Motors Remote Controller Thrust available Propellers Remote Controller Able to turn CW and CCW Battery Battery Charger Able to feed all system Structural Parts Testing Main base Loads on the base Enduring and capable of carrying all parts C.g alignment Rope At the most middle alignment w.r.t rope Controller Parts Testing Receiver Battery Signal detected Board Given inputs Taken Output Remote Controller Buttons Signal detected Flight Test Requirements satisfaction Chronometer and height indicator Endurance(3.5 min) satisfied and height reached(2m) Controllable take-off and landing KK Board Safe take off, flight and landing Table 1 Test plan for different parts and instruments and indicators for them Before the product is given to the customer, the test plan should be made. All of the systems such as electronics, propulsion, structural, controller and finally the flight test with all equipped system. In order to test the parts, some instruments were used and with the help of the test indicators our system was tested in all aspects. 15

16 5. List of References ntroller-v55-qblackboardq&catid=57:pcb-schematics&itemid=65 "The Engineering Design of Systems : Models and Methods", Buede, Dennis M., John Wiley &Sons, Inc.,