Autonomous Following RObot Initial Design Review

Transcription

1 Autonomous Following RObot Initial Design Review James Tse (Leader) Wei Dai Travis Frecker Peter Verlangieri Professor John Johnson ECE 189A Fall 2012

2 Initial Design Review: Project Description Original design: a robot that autonomously draws fields. Issues: Locality Time constraint Expensive

3 Initial Design Review: Project Description (II) Revisited idea: a robot that follows and re-draw existing lines. Applications: Redrawing existing sports fields, e.g. basketball, tennis, football, soccer Repainting fading street lines Perimeter security

4 Initial Design Review: Project Description (III) Base proof of concept goals: Following a line with high precision and accuracy. Using a set of rules to be able to find and trace existing lines, without user input.

5 Initial Design Review: Project Description (IV) Combination of sensors and positioning systems: IR Sensors Sonar Reflectance Sensor Array Digital Compass Rotary Encoders Concept is to load the robot with as much data as possible; if we need it, then we will have it.

6 Initial Design Review: Subsystem Development Responsibility James (leader) - processor, optical sensor, camera, power Wei - PCB, digital compass, power Travis - mechanical - servo, reflective sensor, power Peter - mechanical - motor controls, sensor interface, rotary encoders All: processor, chassis design/fabrication

7 Initial Design Review: Block diagram

8 Initial Design Review: Basic Design 1. Reflectance Sensor Arrays 2. Ultrasonic/IR Sensors 3. Potential Freewheels 4. Wheels 5. Rotary Encoders 6. The guts: controllers, compass, processor, tracing mechanism w/ servo, etc.

9 Parts: Digital Compass Devantech CMPS03 Magnetic Compass Module 0.1 degrees of resolution and 3 to 4 degrees of accuracy Outputs heading via PWM or I2C 5V voltage only Specifically designed for use in robots as navigation aid

10 Parts: Reflectance Sensor Arrays QTR-8RC Reflectance Sensor Array Sensing distance: 3-9.5mm Interface directly to GPIO of microcontroller Operating voltage: V GP2A240LCS0F Sensing distance: 2-22mm Interface directly to GPIO of microcontroller Operating voltage: V

11 Parts: Servo Motor HS-55 Micro Servo Motor Speed (sec/60 ): 0.14 Torque (Kg-cm/Oz-in): 1.3/18 Size (mm): 23 x 12 x 24 Weight (g/oz):8/0.28

12 Parts: Ultrasonic Sensor Maxbotix LV-MaxSonar-EZ0 Object avoidance Detects objects of distance from 0 to 6.45 meters. (0 to ~21 ft). RS V, at 5V - 3mA

13 Parts: IR sensor Sharp GP2Y0A21YK0F IR Range Sensor Object avoidance Detects objects of distance from 10cm to 80cm (4'' to 32''). Output: Analog to Digital V, supply current: 30mA

14 Parts: Motors 2x Pololu 12V Metal Brushless DC Gear Motors $39.95 each 19:1 Gear Ratio 6mm diameter output shaft Integrated 2-Channel Hall Effect Quadrature Encoder Forward/Backward/Brake/Pivot

15 Parts: Rotary Encoders Rotary encoders provide feedback to the microprocessor via GPIO. Frequency of output signal provides speed of the motor and distance traveled. Using encoders on both the right and left wheel allows the microprocessor to calculate and correct offset in traveling in the straight line. 64 counts-per-revolution. Vcc (3.5-20V) Included in motor Well documented by Pololu

16 Parts:Motor Controller Solarbotics L298 Compact Dual Motor Driver Kit $ V Output Up to 4A total output current Allow us to independently control both motors with a single chip Well documented Used by past 189 Capstone Projects

17 Initial Design Review: Preliminary Bill of Materials Quantity Part Unit Cost Total Cost 1 Digital compass $44.61 $ Reflectance sensor array $14.94 $ Ultrasonic sensor $26.95 $ IR sensor $11.75 $ Motor and rotary encoder combo $39.95 $ Motor controller $18.28 $ Servo motor $9.99 $9.99 Total $244.86

18 Initial Design Review: Critical Elements Motor control Keeping the bot in a straight path to avoid rough traces. Reflectance Sensor Array Being able to detect a line in an outdoor environment and use that data to accurately position AFRObot. Currently looking into camera modules.

19 Initial Design Review: Schedule 10/21-10/27 11/18-11/24 IDR - (10/24) PCB layout - M5 (11/18-12/07) Purchase parts - (10/24) Low level hardware implementation - M4 (11/11-11/28) System-level Design - M3 (10/24-10/31) Verilog functional and timing simulations Component selection - BOM Details of intended software structure Collection of data sheets Lowest-level hardware-software interaction Software! MAKEPART Develop parts test plan - (10/24-11/03) 11/14-12/01 10/28-11/03 Milestone #4 - (11/28) Milestone #3 - (10/31) PCB layout - Milestone #5 (11/18-12/07) Test parts (10/28-11/03) 12/02-12/08 11/04-11/10 Critical Design Review - (12/03) Preliminary Design Review - (11/05) Milestone #5 - (12/07) 11/11-11/17 12/9-12/15 Low level hardware implementation - M4 (11/11-11/28) Finals Verilog functional and timing simulations 12/16-01/6/2013 lowest-level hardware-software interaction WINTER BREAK!!! MAKEPART

20 Questions? Suggestions?