P15230 Quadcopter. Detailed Design

Transcription

1 P15230 Quadcopter Detailed Design

2 Presentation Plan Project Overview Review Customer Needs Review Engineering Requirements Electrical Design Mechanical Design Software Overview Path Planning Design Lidar Design Wifi Positioning Design Bill of Materials Risk Assessment Project Planning

3 Project Overview Unmanned Aerial Systems (UAS) are gaining popularity and demand in the commercial sector and for personal, hobbyist use. There is an increasing demand for UAS in areas such as delivery, thermal scanning, and mapping in areas which are time consuming, difficult, or unsafe for a traditional approach. For example, Amazon has announced plans for creating a UAS delivery method for their products. RIT looks to be a pioneer in this field, and has designed a competition based around this idea. The competition will require a fully autonomous craft to pilot itself through an obstacle course, using various methods of object detection to navigate as well as record data. These crafts will also be required to carry and drop payloads during the competition, furthering RIT's research into the UAS field.

4 Customer Needs

5 Engineering Requirements

6 Electrical Design Schematics Test Plans Schematic PCB Layout I/O Connections Communication Protocols Serial i2c Processor Tasks

7 Mechanical Design Structure CAD Models New Part Drawings Updated Weight Study PID Tuning Mechanical Test Procedures

8 Structure (CAD Models)

9 Structure (Drawings) - Sonar Mount/Base Part will be 3D printed using a MakerBot in the RIT Construct Lab. PLA plastic will be used as a material as it has the properties of strength, printing accuracy and is more environmentally friendly than ABS. -MakerBot tolerance to 0.2mm

10 Structure (Drawings) - Rotor Shroud Part will be printed x4 to form one shroud if 3D printing is chosen as final method for manufacturing based on final weight of model after weigh in during MSD II.

11 PID Tuning

12 PID Tuning Cont.

13 Weight Study - updated Thrust (in grams) now overcomes total weight of craft. Mechanical testing will determine vertical acceleration and confirm thrust produced from motors at desired power usage.

14 Mechanical Systems Test Plans Thrust/Weight Spring full assembly weigh in Test max thrust capacity of motors with weighted system and scale Must overcome F=m(g+a). Looking for a positive value of a acceleration Measure vertical acceleration through OpenPilot Durability Fully loaded system weight test on base assembly. Make sure base can withstand resting load in addition to landing forces can make part stronger via comb density in 3D print, but will make heavier. Drop test base with dummy weight to represent fully assembled quad Rotor shroud strength can be tested with similar drop test simulate craft bumping into objects side on while still at proper attitude simulate craft crashing on side to ground

15 Software Overview

16 Master Pi Master controller to all slave devices 2 nano I2C slaves 1 Pi UART slave Functions: plans path to transverse executes movement commands holds global map receives and interprets sensor readings as mapped objects Commands profile camera to snap Able to signal status/faults through GPIO Led Mobius Cam control Takes pictures as for customer requirements within normal resolution and filtering Optional Video streaming for testing

17 Navigation Flow

18 Path Planning Design Local copy of 2D gridded graph which A* Search plans a path resolution of grid has to be smaller than object detection range (sonar ~3m), optimally 0.33m Object detection framework updates graph when an object is detected Simulate A* Search on Pi 2 runs on a complete graph

19 Slave Motor Controller Nano Slave to Master Pi Functions: Interprets commands sent from Flight Controller API Generates PPM signals to send to crafts actuators Detects if user has signaled RC override Able to indicate status/faults through GPIO Led

20 Flight Controller API Flight_Controller_API stop_flag: bool Executing_cmd:bool complete_cmd:bool execmds: list(list(enum cmds,param)) issuablecmds:enum orbit90(int radius offset):bool foward(int dist): bool back(int dist): bool left(int dist):bool right(int dist):bool up(int dist): bool down(int dist):bool stop():bool rotateleft(int deg):bool rotateright(int deg):bool get_execmds: list(int x,y,x) Implement a library of execution safe flight commands to provide basic navigation Commands will have to interface with Nano functioning as a driver for controlled flight.

21 Slave (IP) Pi Slave to Master Pi Functions: Runs Lidar Scanning Relays sensed objects to Master Pi Runs Facial Recognition: relays detected face to Master Pi

22 Facial Recognition Subroutine

23 Lidar Design Lidar uses image processing of projected lasers to measure surface geometry. Lidar based systems are mainly used in 3D scanning and long distance range finding applications Single line Gives surface info Along a Line

24 Lidar Algorithm Using a line laser gives us distances to all points along the line. This can give us an estimate of the surface geometry that needs to be avoided. Blob Analysis and block processing will be used to discretize the line into points. The detected object s surface will be mapped in absolute coordinates. The coordinates will become part of an area blacklist the navigation algorithm will use to plot paths around obstacles.

25 Lidar: Line Tracking Demo

26 Lidar Hardware Raspberry Pi B+ Integrated Graphics Processor Camera Software Support Matlab and Simulink Support User Friendly Raspberry Pi NoIR Camera Module Custom for Raspberry Pi Can capture IR Very lightweight and low profile Can fit standard lense sizes for IR pass filtering Relatively low cost (~$30) 980nm IR Line Laser Very high wavelength for easier filtering from environment light sources Projects a line Invisible to humans Can be powered down to eye safe levels and still be detected by camera.

27 Lidar Test Plan Measure accuracy and resolution on test Rig. Map random objects at various orientations Evaluate camera performance in competition area. IR Isolating Adjust such as exposure and contrast Camera parameters Test communication with navigation computer Evaluate processing speed requirements from other system tests. Evaluate measurement resolution requirements from other system tests Full system interaction testing. Current Test Rig

28 Slave Sonar Sensing Nano Slave to Master Pi Relays information back to the Master Pi Functions: Collects sonar distance readings Takes readings of current and voltage sensors Relays sensor readings back to Master Pi Relays compass heading retrieved from compass sensor back to master Pi Able to indicate status/faults through GPIO Led

29 Wifi Positioning Design Main Positioning Equations Re-Orienting Equations Wifi Distance Reading Code Results of Preliminary Wifi Distance Tests

30 Wifi Positioning Hardware Raspberry Pi B+ Algorithms are integrated with Pathing software already on the Pi. 3.3V logic allows for easy communication with other components also using 3.3V logic. Wireless Router Need a basic router just for signal strength calculations. Limited field area reduces the need for more power or higher-end routers. Exact router to use TBD.

31 Power Management Voltage Sensing(Battery level) Current Sensing

32 Benchmarking-Power Management # of Resistor required[ohms]- 2(both) # of capacitors required[farad]-2(both) Requires additional circuitry Cost[Dollar-$]- Less expensive for voltage divider Space constraint- less space for voltage divider

33 Current sensing # of Resistor required[ohms]- two for both but Opamp needs special Rsense resistor Hall effect sensor bandwidth can be adjust with an external capacitor Hall effect is more reliable and less expensive Halle effect uses flip chip technology

34 Constant Current for LIDAR Can deliver up 40mA plus of current depending on Vcc Has control signal pin and Enable Low power

35 Software Test Plans Dynamic environment path planning a. Simulate object detected to randomly force updates to global map ( also proves component interaction on master Pi) b. Integrate with actual sensor readings to map as obstructions on global map i. sonar sensors( also proves slave Nano and master Pi communication) ii. Lidar sensor (also proves slave Pi and master Pi communication) Computer guided flight control (execution of moves) a. Create local (on Nano) test movements: lift, land, rolling,advance,distance, rotate (yaw) b. Create a library of basic navigation commands, should be executable a neutral (static hovering position) c. Test consecutive executions of commands from non-neutral positions

36 Software Test Plans cont Facial recognition a. Import and train Voila-Jones OpenCV classifier to at least 90% accuracy b. Apply program in a simulated (manual) search movement. Trilateration a. Test signal interference of multiple routers: accurate calculation of radial distances for 3 routers b. Implement Trilateration and measure variance of coordinates calculated vs. measured Navigation flight command integration a. Test craft ability to follow a planned path using flight controller API (none obstacle) b. Test integration for large easily recognizable objects (such as walls)

37 Bill of Materials Bill of Materials

38 Risk Assessment

39 Project Planning Path Planning Planning

40 Project Planning

41 Project Planning Mechanical Planning

42 Project Planning

43 Project Planning Lidar Planning

44 Project Planning

45 Project Planning Wifi Positioning Planning

46 Project Planning

47 Project Planning Electrical Planning

48 Project Planning