UAVPresented By: • Alexander Mohamed Osman • Riyad Ahmed El-laithy • Ruyyan Ahmed El-laithy • Peter Raouf Zaki
Introduction• What are UVs ?• What are UAVs ?• Types of UAVs – Fixed wing UAV – Helicopter UAV – Quadroter UAV
Quadrotor Advantage Over Fixed- Wing Vehicle• Less design complexity.• Minimal space for take-off and landing. A VTOL vehicle.
Quadrotor Advantage Over Helicopter• Quadrotors do not require mechanical linkages.• The use of four rotors allows each individual rotor to have a smaller diameter than the equivalent helicopter rotor.
Control Scheme Direction ∆ Motor 1 ∆ Motor 2 ∆ Motor 3 ∆ Motor 4 Z+ (Up) + + + + Z- (Down) - - - - X+ (Left) + 0 0 + X- (Right) 0 + + 0Y+ (Forward) + + 0 0Y- (Backward) 0 0 + +
Materials used in building the Prototypes• Balsa wood planks• Super glue
The First Prototype:• Disadvantages – It was too heavy to lift • 197 grams. – The spacing between the motors Picture of 1st Prototype
The Second Prototype• What is improved in that prototype ? – The weight decreased • 93 grams. – The motors are closer to each other• The result Picture of 2nd Prototype – Light lift
The Second Prototype• Disadvantages – Still heavy to hover – Disturbance in the rotor wind vortex – Not aerodynamic Picture of 2nd Prototype
The First Prototype VsThe Second Prototype
The Third Prototype• What is improved in this prototype ?- Starting the X design- Reduced air resistance.- More lift gained .- Lightweight . • 45 Grams. Picture of the 3rd Prototype
The Third Prototype• Problems with the new design: – Too fragile. – The reduced air resistance was still not enough.• What can be done ?
The Fourth and Final PrototypeTop: Isometric: Front: Side:
The Fourth and Final Prototype• Achievements: - Rigid and Lightweight. (43 Grams). - Great lift. - Highly reduced air resistance. Picture of Final Prototype
The Fourth and Final Prototype• Specifications: -Total Weight (with all components) = 990 Grams (0.99 Kg) - Acceleration at Full Power = 4.061m/s2 - Vertical Force at Full Power = 4.021N (Assuming Differential Torque = 0) - Lateral thrust beyond Hover Thrust = 0.4141g - Power – to – Weight Ratio = 1.5 : 1
Controller Design• Design Objectives – Stability – Obstacle Avoidance – Determining Position – Communication
Controller Design• To achieve these objectives we need – IMU (Inertial Measurement Unit) – 5 Ultrasonic Sensors – GPS Receiver – RF Transceiver
Controller Design• MicroController requirements – 4 PWM Outputs – 11 Analog to Digital Channels – High speed crystal• PIC18F4431 – 4 14-bit Power PWM modules – 9 10-bit 200Ksps ADC channels – 40 MHz Crystal Max
Controller Design• Problems with PICxxFxxxx – IMU and RF work at 3.3V Logic – GPS messages are TTL 0 – 2.85V – Ultrasonic readings range from 0 – 2.54• PIC16LF777 – 3 10-bit PWM modules – 14 10-bit ADC channels – 10 MHz Crystal max – Operating voltage range from 2V – 5.5V – 2 Connected together
Controller Implementation• Small & compact design• Easily modified – Modify subparts only – Protect components from repetitive exposure to welding temperatures• Sub boards• Interface PCBs (Printed Circuit Boards)
Controller Design• First Main board – Replaced – Photo-couplers were used later on
Controller Design First Main board
Controller Design• Second Main board – Photo-couplers were implemented – Sub-boards implemented – Interface boards – Smaller design
Controller Design Second Main board
Controller Design• Last Main Board – Photo-couplers – Interface boards – Sub-boards – 90° Interface connections – Even smaller design – ICSP (In Circuit Serial Programming) wires were added onto the circuit later on – LEDs for easier debugging without the need for expensive hardware such as ICDs (In Circuit Debuggers)
Controller Design Last Main board
Controller PCB Implementation Last Main board
Interface Boards• Easier error correction.• Reduction of surface area.
GPS Interface Board
IMU Interface Board
RF Interface Board
PCB Production Procedures• What do you need to make a PCB – Laser printer – Glossy paper – Acetone – Clothing iron – Acid – Steel sponge
PCB Production• Clean the surface of the board• Print the circuit• Start folding• Start ironing• Put it in hot water• Start chemical etching• Finalize with drilling
Analog-To-Digital Converter• ADCs: - Importance of Data Acquisition in our UAV. - Vref set on 3 Volts. - Ultrasonic sensors. - Gyrometer. - Accelerometer.
ADCs• ADC Reading = (Vin/Vref) X (2N); where Vin : is the Voltage input. Vref : is the reference voltage. N : is the resolution of the ADC Conversion.
Ultrasonic Sensors• Ultrasonic Sensors: - Maximum Range: 254 inches (6.45m) - Minimum Range: 6 inches (15cm) (Blind Spot) - New Readings every 49 Milliseconds. - Has Serial/Analog/Pulse Width Modulation output. - Every 0.01V represents 1 inch.
Ultrasonic Sensors• Calculating Distance inside ADC: - Distance = (Vin/Vref) X (2N);• For example: 50cm = 0.20 Volts shown on Ultrasonic Sensor. (0.20/3.30)*1024 = 62.061 To calculate backwards to know accuracy: (62/1024)*3.3 = 0.1998 Volts on input pin. Therefore, the Error = (1-(0.1998/0.20))*100 = 0.1%
PWM• Pulse Width Modulation: - Processing after Data Acquisition for scenarios. - Implementing the data acquired as output on Motors. - Frequency for Motor Output (750Hz).
PWM• How It works? Obtains Average of On/Off Intervals within period.• VAV = 1.65 Volts since half the time is ON and the other half is OFF.
Testing Sensors• A great way to test the sensors is using an LCD. – Tangible.• Used to test all sensor outputs after processing: - Ultrasonic. - Accelerometer. - Gyrometer. - GPS Receiver. - RF Transceiver units.
GPS Applications• GPS has become a widely used aid to navigation worldwide.• A useful tool for – Map making. – Land surveying. – Scientific uses.
NAVSTAR Constellation• There is a constellation of 30 earth orbiting satellites transmitting precise radio signals.• Orbits are set up so that at any given point and time on the earth’s surface there are at least six of these satellites in reach.
GPS Messages• Almanac contains orbital data• Ephemeris contains the satellites precise orbit.
Pseudorange• Estimated distance calculated by the receiver between the satellite and receiver.
Trilateration• Pseudoranges intersect at a point.• This point is the receiver location.
Latitude & Longitude
NMEA Protocol• NMEA preferred to SiRF.• Simply works with input and output messages.
Input Messages• Input messages are used for initialization.• Selected input messages were: – Set Serial Port – Query/Rate Control – Development Data On/Off• CRC required for input message.
Output Message• Message of choice was RMC, it contained all we needed which was: – Latitude & Longitude – Course Heading – Velocity
USART• The GPS communicates with the PIC through USART.• Communicates at 4800 bps• Asynchronous
Validating Message• When the message is validated: – The latitude, longitude and heading are ready to be extracted to the Main PIC. – RF function is called to transmit data, to the simulator.
Inertial Measurement Unit• Gyro – Measures angular velocity on the x and y axes – Can also be used to calculate displacement angle – Sensitivity of 2mV/°/sec
Inertial Measurement Unit• Accelerometer – Measures acceleration on the x,y and z axes – Sensitivity of 300mV/g – Can also measure angles
Inertial Measurement Unit• IMU – Gyrometer & Accelerometer – Transform acceleration readings onto the 3 original axes. – Velocity & Displacement can be calculated from accelerometer readings on 3 main axes.
Inertial Measurement Unit
Microcontroller Communication• SPI Communication – Master/Slave Configuration – 3 pin connection – Synchronous Serial Transmission – 8-bit at a time – Control Messages, & Sensor Values
Laipac RF• Haw the transmitter works ? – Data input to the to the encoder. – transmitting the data
Laipac RF• The transmission unit
Laipac RF• How it receives? – Data receiving – Data decoding
Laipac RF• Receiving unit
Laipac RF• Conclusion after testing – Too slow. – Big size . – Very small payload. – Very short range. – Need an external antenna.
RF-24G transceiver• Specification – Very small size – Long range » 280 meter – Built in antenna – 29 byte payload – Fast transmission & reception » Up to 1Mbps – Shock burst mode
RF transceiver• States of Shock burst – Active mode – Configurations mode – Standby mode – Power down mode
Data Acquisition• What is Data Acquisition?• Why?
Data Presentation• What is Data Presentation?• Why?
Problems• Serial Port• Signed Byte• Graph Origin• Converting Longitude and Latitude to Pixels
Solutions• Javax.comm -CommPortIdentifier -Streams -SerialEvent -Converting any data to String then to Bytes• Convert to short add 256 if negative• -( ( (Height - 90 ) / Range ) * Actual ) + Separation• ((width /|(difference between top left longitude and bottom right longitude)|)*|(acquired longitude-top left longitude)|)
Data Presentation Platform
Data Presentation Platform (cont.)
Remote Control (cont.)
Introduction• What is an object ?• What is object detection ?• How to make it ?• What is image processing ?
Challenges & solutions• Acquisition problems• Developing imaging application in a flexible environment• Why not use c/c++ ? – Time consuming , handling• Used language, Why ?
Imaging circumstances• Type of the acquistion• The properties of the target object?• The environment• The objective
Challenges• Colored image• Variance in lighting• Uninformed background• The target is colored• The target’s shape is not defined
Our program• Acquisition phase• Visualization phase – Estimate the degree of the color• Processing phase – Applying Median filter
Analysis phase• Make a binary image showing the blue pixels• If there is other blue objects it will be shown as white objects
• Pixel connectivity• The use of the labeling function – [label,num]=bwlabel(y,4); – stats=regionprops(label,Area,BoundingBox, PixelList);• What are the importance of those functions
• Finding the object with the largest area• Locating its position• Making a bounding box around• Send the target position to the UAV
Screen shots• Idle mode
Screen shots• Running mode
Screen shots• Running mode(object not found)
FUTURE IMPLEMENTATIONS• Gyrometer & Accelerometer drift correction• Ultrasonic sensors attached to servos.• High powered brushless motors.• A long range high resolution camera.• Magnetometer• Chassis redesign
CONCLUSION• Local market restrictions inhibited time.• Bottom down programming was the best approach.• Data presentation helps in detecting errors faster and avoiding problems.• Placing UAV on a map helps discovering its location.• Tester helps in testing the response of the RF and the pic programs