Tiger Scramble Tiger Scramble Robot Design Hannah Hoppenstedt Josh Nelson

Presentation Outline Major Component Connections Operations Subsystems and Components –Requirements –Component Specifications Budget

Major Component Connections RF Receiver BS2BS2p 40 Bumper Switch Servo MMC Motor CommunicationBall Control Brains Locomotion

Operations Find closest ball to goal Travel to and capture ball Put ball in goal Avoid opponent robot

Subsystems and Components Microcontrollers Locomotion –Motors –Wheels Ball-Control Apparatus Battery Chassis

Communication Requirements Receive data from vision system –Want to receive every packet –Do not want BS2p40 tied up for 33 ms per packet

Basic Stamp 2 Receives info from the vision system Sends the data to the BS2p 40 for calculations –At the maximum flow control baud rate of 19.2k, it takes 3.75 ms to send 9 bytes BS2 to BS2p Connection (4 I/O pins) –One pin for serial data transfer –One pin for flow control –Two pins for handshaking

AI Requirements Calculations on vision system information –Distance –Angle –Integer Comparison Interpret commands from Vision System Execute all functions between packets –100 ms between first bits of two consecutive packets Memory –53 Bytes

Basic Stamp 2p 40 AI Requirements RoutineMemory Required (Bytes) Pick Ball29 Go To Ball16 Go To Goal3 Avoid Opponent5 TOTAL53

Control Requirements Component Connection Sufficient number of I/O pins –Control servo (1) –Bumper switch (1) –Motor Mind C (2) Fill registers on MMC to control speed and direction –BS2 (4) Need 8 I/O pins

Basic Stamp 2p 40 AI RoutineExecution Time (µs) Pick Ball8,220 Go To Ball1,150 Return To Goal1,150 Avoid Opponent1,138 TOTAL11,658

Basic Stamp 2p 40 AI Connection –Need 8 I/O pins –BS2p 40-pin module has 32 general purpose I/O pins Memory –Need 53 bytes –BS2p has 128 bytes of scratch pad RAM and 26 bytes of variable RAM

Locomotion Requirements Motor Control Motors –Motor Mounts Wheels –Wheel hubs

Motor Control Requirements Generate pulse width modulation –Speed control Provide adequate current to motors

Motor Mind C Generate pulse width modulation –Duty cycle of PWM varied according to register value in serial mode Includes 2 H-Bridges –Current control Connected to each motor with three output lines

Motor Requirements Sufficiently low stall current –1.5 A Lightweight Speed –0.5 m/s Torque –Minimum oz-in

Copal Gearmotor 60:1 Stall Current1.6 A Rated Current400 mA Weight0.88 oz Rated Voltage6-12 V Torque21 oz-in

Motor Mount Lexan Light weight –4 grams Simple assembly

Wheel Requirements Provide adequate ground clearance –Minimum of 2 cm Shock absorbent for motors

Lite Flite Wheels Foam –Light weight 11.3 g each –Shock Absorbent Ground Clearance – 6.35 cm diameter wheels 3 cm

Ball-Control Apparatus Gripper –Simple design –Detect Ball Capture Bumper Switch –Ball Capture Servo and armature

Ball-Control Apparatus Detect Ball Capture –SPDT Switch –SL-2NW1 Ball Capture –Servo and armature –Futaba Continous Rotation Servo

Battery Requirements 12 V –Speed control flexibility Withstand 15 minute rounds –0.3 AH at 12 V

Battery Usage ComponentVoltage(V)Current(A)% UsagePower (W) 2 Motors63.24% (stall) % (normal)9.216 BS2p %0.375 BS2-IC %0.2 Motor Mind C %0.36 Servo %1.2 5 V regulator %2.254 Receiver %0.035 TOTAL14.4 Capacity = Total Power / 12V * (15 / 60) = 0.3 AH

12-V 500 mAH NiMh Brick AntPack 0.5 AH exceeds required 0.3 AH Meets 12 V requirement Run Time = 25 mins.

Chassis Requirements Space availability Allow easy access to parts Flat black top Flat front for ball control apparatus Lightweight Durable

Expanded PVC Weight –450 g with standoffs Weight Limit –4 kg –Need 750 g Easy to design and build a robot out of this material Easy to implement multiple decks

Bottom Chassis layer Battery

Middle Chassis layer BS2 BS2p MMC Servo Receiver Bumper Switch

Top Chassis Layer

Budget Revision 2

ItemQuantityPrice per Unit ($) Motors & Mounts Wheels & Hubs27.35 Motor Mind C BS2 - IC BS2p PCB Chassis19.38 Battery Gripper TOTAL382.40

Conclusion Simple design Meets requirements –Speed –Microcontroller capabilities –Ball control Within budget

Questions or comments?