Transcript Solar Panels Specifications

PowerBot
Group #2:
Tarik Ait El Fkih
Luke Cremerius
Marcel Michael
Jerald Slatko
Sponsored By: Aeronix, Inc.
Project Description
 Autonomous Robot with onboard auxiliary
battery
 Used to provide supplemental power to mobile
devices (laptops, mobile phones…etc)
 Uses onboard navigation algorithms to
navigate to users location
 Has iOS application to provide robot statistics
and is used to control PowerBot’s movements.
Project Motivation
 Battery life longevity in mobile devices is a constant
issue.
 Wanted to create a charging solution that could charge
the device without inconveniencing the user.
 The device would be simple to use, allowing for easy
adoption into a users everyday routine.
Objectives
 PowerBot will be able to navigate autonomously to a
users location.
 PowerBot can be remotely controlled by user input,
through the use of an onboard camera and the
provided iOS application.
 PowerBot will contain a battery used to charge external
devices through the use of USB, DC, and inductive
charging.
Specifications
 Will be at most 36” long
 Max speed of 5 mph
 Battery life of minimum 24 hours
 Able to charge mobile phone from 0% - 100% without
needing to recharge internal batteries
 Will re-charge internal batteries through in-home AC and/or
via onboard solar panel.
 Will navigate to the user autonomously
 Can be operated via manual control
Obstacle Detection
 Half-ring of eight ultrasonic
sensors
 One or two sensors on back
to serve as bumper
 Rapidly ping the environment
to detect objects within a
~200° arc
 Sensor pinging is carefully
timed to avoid cross–talk
 Sensors operate on I2C bus
to be individually addressed
using only two wires
Ultrasonic Sensor
I2CXL-MaxSonar® – EZ3™

Operates at 3V – 5.5V

Avg. current draw: 4.4mA

Min. Distance: 20cm
 Obstacles closer than 20cm give
reading of 20cm

Max. Distance: 765cm (25.1ft)

1cm Resolution

Readings taken at 15Hz to 40Hz depending
on distance measured

Beam spread between 20° and 40°,
depending on shape and distance of
detected object

Real-time auto calibration (voltage,
humidity, noise)
Photo Credit: www.maxbotix.com
EERUF
 Error Eliminating Rapid Ultrasonic Firing
 R&D credit to Dr. Johann Borenstein
 Reduces erroneous readings by up to two orders of magnitude!
 Each sensor has two unique timing delays
 Consecutive readings in a sensor are compared
 Readings due to cross-talk can be identified and rejected if they fall
within a timing outside of the receiving sensors’ timing
 Timing parameters must be experimentally determined
VFH Navigation Algorithm
 Vector Field Histogram (VFH)
 Researched and developed by Dr. Johann Borenstein
 Autonomous real time navigation (moves without
stopping)
 Utilizes an array of ultrasonic sensors
 Rapidly takes readings while moving to update
obstacle and localization information
 Sufficient for speeds close to 1.5m/s
 Extensible to include trap detection heuristics
How Does VFH Work?
 Collect ultrasonic range information, map to a
Cartesian certainty grid
 Certainty grid is a 2D array with values between 0 and 15,
representing the certainty that an obstacle exists at that
point
 This grid is converted to a visual map for the phone app
 Certainty grid is mapped to a polar histogram
 A polar slice has information about the density of
obstacles in that direction
 A candidate direction is chosen by comparing the
directions of unobstructed paths to the target direction
Image Credit: Dr. Johann Borenstein
Example Scenario
Image Credit: Dr. Johann Borenstein
Example Scenario – cont’d
Image Credit: Dr. Johann Borenstein
Example Scenario – cont’d
Image Credit: Dr. Johann Borenstein
Example Scenario – cont’d
Image Credit: Dr. Johann Borenstein
PIC32 Microcontroller
 PIC32 family of microcontrollers was chosen to drive
PowerBots navigation and Wi-Fi communication
functions
 The PIC32 features an 80MHz clock with an onboard
512Kb of flash and 64Kb of RAM
 Model Number: PIC32MX695F512H-80V/MR
Wi-Fi Communication
• Used as the primary mode of communication between PowerBot and the iOS
application.
• 802.11 used as physical layer communication with sockets used for higher
level communication.
Embedded Software
iOS Software
Application
Layer
Application
Layer
MCU – Serial
iOS – Serial
802.11 – Socket
802.11 – Socket
Wi-Fi Module: MRF24WB0MA
• The MRF24WB0MA microchip provides a complete Wi-Fi solution for
onboard communication with PowerBot.
• The integrated TCP/IP stack within the MRF24WB0MA allows for easier
implementation of sockets and the passing of data via TCP/UDP.
Power Consumption
• A low power communication solution.
• Power features:
• 250 𝜇A when in sleep mode
• 85 mA when active and connected
• 154 mA when active and transmitting
Wi-Fi Operating Modes
Sleep
Receiving
If no
message
received in
time interval
Awake
Receiving
Awake
Transmitting
Development Board
 DV102411 chosen as
development board
 Combines PIC32 MCU with the
Microchip Wi-Fi module
 Model Number:
PIC32MX695F512H-80V/MR
Wi-Fi® Comm Demo Board
(Part # DV102411)
Software Layout
iOS
Application
PowerBot
Embedded
Navigation
Algorithm
Motor Control
Power
Management
Sonar
Sensors
Servo Motors
Solar Panel
Charging
Ports
iOS Application
 Written in Objective-C using
Xcode 4.4.
 Offers multiple options for
PowerBot:
 Settings
 Navigation
 Manual mode
 Statistics
iOS Views
 Each view contains a
separate viewController
allowing each tab to
contain a unique layout
of buttons and fields to
be presented to the
user.
Navigation
 Contains world map information
which recognizes touch gestures
as a method of input.
 Allows the user to select a
location on the map for PowerBot
to travel to.
 Shows PowerBot’s current
location within the world map.
Manual Control
 Gives the user manual controls to
drive PowerBot.
 We are considering including a
video feed along with manual
control
System Statistics
 Shows the user the current status
of PowerBot.
 Displays remaining battery power.
 Display the current mode of
operation:
 Sleeping
 Charging
 Navigating
System Settings
 Will allow the user to adjust
settings for PowerBot’s operation:
 Connect to a different Wi-Fi
network.
 Timeout interval before activating
sleep mode.
Power
9 V Reg
6V
5V
6 V Reg
3.3V
DC Motors
12V
Inductive
Charger
Obstacle
Avoidance
5V Reg
PIC 32
3.3 V
Reg
Servo Motors
WIFI module
USB
Compass
Battery Requirements
 12 V battery
 At least 2 Ah
 Deep cycle for increased usage time
 Low internal resistance
 Flat discharge rate
 Lightweight
Battery Choice
SPECIFICATIONS
Ni-Cd
Ni-MH
Li-ion
Li-Po
Energy Density (W·hr/kg)
40–60
70-90
100-160
130-200
Capacity (Amp-hr)
1
2.4
2.8
2.6
Internal Resistance (mΩ)
100-200
200-300
100-200
200-300
Nominal Voltage (V)
1.2
1.2
3.6
3.7
Discharge Rate
Flat
Flat
Flat
Flat
Recharge Life
500-700 cycles
600-1000
>600
>1000
Disposal
Must be recycled
Recyclable
Recyclable
Recyclable
Charge/Discharge
Efficiency
70-90 %
66 %
80-90 %
99.80 %
Cost ($/Whr)
2
2.75
2.5
2.8-5
Lithium Polymer Battery
 Polymer Li-Ion Battery





18650 cell type
14.8 V (working)
16.8 V (peak)
2.2 Ah
32.56 Wh
 Reasons for choosing:
• High energy density (Wh/kg)
• High energy/dollar (Wh/$)
Alternative Power Source
 Power outlet:
 “Unlimited” power
 Quick charging of the battery
 Solar panel:
 Environmental Impact
 Financial Benefits
 Energy Independence
Solar Panels Specifications
Monocrystalline
Polycrystalline
Thin film
Power
10 W
10 W
10 W
Open Circuit voltage
21.5
21.4
24.2
Short Circuit Current
0.64
0.68
0.84
Maximum Power Voltage
17.5
16.8
17.3
Maximum Power Current
0.57
0.6
0.64
Efficiency
15 %
12.5 %
6.3 %
Cost/W
10-11
8.5-9.5
10
Solar Power Selection Details
Solar Panel Type
Monocrystalline
Manufacturer
INSTAPARK
Efficiency
15 %
Power
10 W
Maximum Voltage Power
17.5
Maximum Current Power
0.57 A
Open Circuit Voltage
21.95 V
Cost
$39.95
Output Efficiency
 Increasing the output efficiency of the panel:
 Increase panel size
 Implement tracking system
 Single axis
 Dual axis
Single Axis Control System
Ambient Light
Photoresistor
MSP430
Longitude
Orientation
Dual Axis Control System
Latitude
Orientation
Ambient
Light
Photoresistor
MSP430
Longitude
Orientation
Compare and Contrast
 Dual axis control system would require more
maintenance.
 There’s an extra cost involved in utilizing an extra
motor or actuator.
 Increased complexity.
 6% extra efficiency compared to a single axis control
system; not worth it.
Solar Panel Implementation
 Free rotation of theta
(𝜃) angle.
 Phi (𝛷) is fixed in
single axis system.
 Optimal angle of phi
(𝛷) is 15°.
Servo Motor Specifications
 Control System: +Pulse Width Control 1500usec Neutral
 Required Pulse: 3-5 Volt Peak to Peak Square Wave
 Operating Voltage: 6.0 Volts
 Operating Speed : 0.15sec/60 degrees at no load
 Stall Torque: 51 oz/in (3.7 kg/cm)
 Current Drain: 7.7mA/idle and 180mA no load operating
 Dimensions: 1.57" x 0.79"x 1.44" (40 x 20 x 36.5mm)
 Weight: 1.52oz (43g)
 Price: $12.95
Budget
Part
Cost
Quantity
Total Cost
RC Car
Chassis
$50
1
$50
Solar Panel
$40
1
$40
Inductive
Charger
$40
1
$40
Battery
$105
2
$210
Dev Board
$50
1
$50
PICKit 3
$50
1
$50
Sonar
Sensors
$30
10
$300
Motors
Circuit
Components
Total
Distribution of Labor
Topic
Tarik Ait El
Fkih
Luke
Cremerius
Marcel
Michael
Jerald
Slatko
Solar Panel
80%
5%
10%
5%
MCU Software
25%
25%
25%
25%
Robot Construction
10%
5%
80%
5%
Wireless Design
5%
70%
5%
20%
Navigation/AI
5%
20%
5%
70%
Concerns
 Accurately depicting a global map and linking it to
PowerBot’s local map
 Correct implementation of the EERUF Method
 PowerBot becoming stuck in a trap situation
Questions?