Transcript Document

Team Ninja
Introduction/Overview

Implementation of Subsystems
– MCU board
– Chassis/Motor/Motor Driver
– Sensor
Parts List
 Schedule
 Division of Labor

MCU Board
MCU Board Block Diagram
MCU Pinout
MC68711K4 Microprocessor
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Features
– 8-bit opcodes and data
– 16-bit addressing
– 8 A/D Converters
– 4 PWM signal
generators
– Non-multiplexed
address and data lines
Timing Diagram
XC95108 CPLD
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Implementation
– Chip select device
– All other on board logic
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CPLD vs FPGA
– Simpler
ECS-2200B Clock
Clock for the
microprocessor
 8 MHz speed
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Reset Button
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Input that resets our microprocessor
 Inverters de-bounce signal
AT29C256 EPROM
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Features
– Fast read access time –
70ns
– Fast program time
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64 byte program time –
10 ms
Chip erase time – 10 ms
– Typical Endurance >
10,000 cycles
EPROM Timing Diagrams
Samsung 428 SRAM
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Features
– Organization 32K x 8
– Low Data Retention
Voltage
Power System
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MC7805 Voltage
Regulator
– Outputs Steady 5V
– Large Input Voltage
Range (7.5V – 18V)
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Power Busses
 Bypass Capacitors
(0.1uF)
Infrared Sensors

Using Sharp GP2D120 IR sensors
– Max of 8 sensors (high cost)
 Above, below, and forward sensors
– Analog Output
 Consistent voltage curve vs distance
– Low power consumption
 150 mW / sensor max
IR Sensor limitations
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High Cost per unit ($15)
– Unfeasible to be covered on all sides

Need to ensure unit always “looks forward”
before driving
– Up to 8 sensors on front side
 Positioned to see:
– Directly forward
– 45 deg angle upward of directly forward
– 45 deg angle below directly forward
Infrared Sensors
Infrared Sensors
Output Characteristic
0-15 cm to right
Device 1 and 2 averages and spec sheet
0-50cm below
3
Datasheet spec
Device2avg
Analog output voltage (V)
Device 1 and 2 averages and spec sheet
3.5
Analog output voltage (V)
3
2.5
Device1avg
2.5
2
1.5
1
2
Datasheet spec
Device2avg
0.5
1.5
0
2
4
Device1avg
6
8
10
Distance to reflected object (cm)
1
0.5
0
0
5
10
15
20
25
30
Distance to reflected object (cm)
35
40
45
50
12
14
A/D Conversion
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HC711K4 provides 8 multiplexed inputs to
an A/D converter
 Continuously sample inputs
 IR sensor directly connected to multiplexed
MCU input
A/D Conversion


Provides 8 bits of resolution
Output of A/D converter is $00-$FF stored in register
– VRH controls maximum voltage seen
 Will use VRH = 3.0 V
 Sampled Voltage > VRH
– Data stored = $FF
– VRL controls minimum voltage seen
 Will use VRL = 0.8 V
 Sampled Voltage < VRL
– Data stored = $00
– Linearly scaled in between $00 - $FF
– 8.5 mV resolution using above VRH and VRL
A/D Reconstruction

Convert Voltage-Distance table to $00-$FF format for
easy lookup
– $00 = 15 cm…$01 = 15 cm…$FE = 3cm…$FF = 3cm
Constraint: Need to know how close to wall start
position is

Fix: always start more than 5cm away from wall
Device 1 and 2 averages and spec sheet
3
Datasheet spec
Device2avg
Analog output voltage (V)

Device1avg
2.5
2
1.5
1
0.5
0
2
4
6
8
10
Distance to reflected object (cm)
12
14
A/D Reconstruction
7-Segment LED
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7-segment LED displays
current position
– 1 display per sensor
 Hex display
– 3-9 cm displayed as 3-9
– 10-15 cm displayed as A
–F
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Assistance in debugging
movement
– Why did it turn when it
wasn’t even near a wall?
A/D Reconstruction
7-Segment LED Implementation
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
Encode distance measurement into
signal displayable by 7-segment
LED
Write result to $2000-$2FFF
– Reserved for LED latches by CS CPLD

Latch this data using 8-bit latch
– Connect to display with pull-up resistors

3-F displayed on 7-segment LED
Battery Power
Constraints

MCU board requirements:
– 8V - 30V



Voltage regulator limits to 5V, 1A
Max of 1000mAh
Motor requirements:
– 2000mAh / motor

Step-up voltage to ~10V
 Monitor battery charge to prevent going below
10% charge
Battery Power
Solution: Tether


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5000mAh batteries
expensive, heavy, and/or
difficult to recharge
Tethered approach 1 or 2
cables attached to exterior
power supply
Too complicated to
complete on time
Focus of project:
intelligent movement of
device
Programming:
Overview
Always
Move Forward
No objects detected
IR Check
Check for obstacle
Turn, Change
Direction
Object
detected
Programming:
Moving Forward
No
Object
Detected
Set internal
Latch
Move
Moving N/S
Turn Forward
Both
On
Motor
PWM
Count Steps
Driver
Moving E/W
N/S
PWM
Step
~200Hz the
Motor
Count Steps
E/W
Always
Programming: IR Check
Always
Initialize
A/D
IR sensor’s
A/D conversion
Result register
Distance
Estimation
Calculation
7-seg LED
latch
7-seg
LED
Compare to VoltageDistance table
Object
Detected
Objected Detected?
No Object Detected
Threshold
i.e. 4 cm
Object detected
(straight ahead)
Set
R wheel
latch
Programming:
Turning
(Always Turn Left)
R wheel forward
R Wheel
Motor
Driver
Check
for
obstacle
PWM
~200 Hz
Clear
L wheel backward
L wheel
latch
Rotate
Direction
45deg
L Wheel
Motor
Driver
Done Turning
STP-MTR-17048 Bipolar Motor
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Stepper Motor
1.8 degrees/step
Lightweight
6.0 lbs Maximum Load
2.0A Rated Current
0.59Nm Maximum
Holding Torque
Motor/Driver Works Best
Above 200Hz
Motor Needs at Least 16W
of Power
Bipolar Stepper Motor Driver

One Driver for Each
Stepper Motor
 Powered at 8-30V
 Direction
 Step
 Optoisolation
 Dual H-Bridge
Chassis Assembly

1.65ft Diameter
 Round
 Plexiglas
 Swivel Wheels
Vacuum

14.4 V
 30 Watts
 7.2V Rechargeable Battery
Parts List

STP-MTR-17048 Bipolar
Motors (2)
 Quasar 3158 Bipolar Stepper
Motor Driver (2)
 3”x13/16” Wheels (2)
 Swivel Wheels (2)
 Sensors (8)
 Plexiglas Chassis
 HC711K4 Microprocessor
 XC95108 CPLD
ECS-2200B
Clock
AT29C256 ROM
Samsung K6x0808C1D-DF70
RAM
MC7805 Voltage Regulator
7-Segment LEDs (8)
Vacuum (Black and Decker
Cyclone)
Schedule
Status

Connects Motor With U-Bolts
 Done With Chassis Assembly
 Done With Sensors
 MCU Board connected and running
 CPLD Programmed
 Processor Resetting Correctly
 ROM connected
Plan of Attack

Milestone 1
– MCU board completely done
– Sensor input to MCU
– MCU output to motor drivers
– Basic vehicle movement

Milestone 2
– Intelligent movement based on sensor input
– Integration of vacuum
– User interface
Division of Labor
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

Kevin
– Microcontroller Programming
– MCU board
– Communication Between Devices
Tim
– Peripheral Sensors
– MCU board
– Sensor Logic
Simone
– Mobility Functions
– Chassis
– Mobility Logic
– Track Distance/Make Internal Map
– Vacuum Integration
Conclusion

Implementation of Subsystems
– MCU board
– Chassis/Motor/Motor Driver
– Sensor
Parts List
 Schedule
 Division of Labor

Questions?

[email protected]
 [email protected]
 [email protected]