Final Spring 2003 Presentation

Cornell BattlebotsSpring 2003 Review: 

Cornell Battlebots Spring 2003 Review Team Leaders: Justin Manzo, Edward Kelleher, Adam DuChene, Jason Harris Team Members: Ryan Connell, Melody Hung

Semester Review: 

Semester Review Justin Manzo

Accomplishments - Weapons: 

Accomplishments - Weapons Weapon Prototype functional First iteration proved feasability Second iteration attempted functionality Final design accommodates previous shortcomings

Accomplishments - Drivetrain: 

Accomplishments - Drivetrain Drivetrain developed gearing solutions Prototype gearbox developed Hub designed, implemented, redesigned to accommodate changing weapon designs Motor mounts created

Accomplishments - Framing: 

Accomplishments - Framing Initial Frame implemented Facilitates communication between drivetrain and weaponry groups – major inconsistencies Allows for potential placement of components Second Frame designed, under construction Meets demands of all subteams, fully optimized

Accomplishments - Electrical: 

Accomplishments - Electrical Motor controllers finished, fully functional Control board designed, printed, assembled Control logic generated Initial radio contact made in lab environment

Accomplishments - Managerial: 

Accomplishments - Managerial Funding allocated for entire Spring 2003 budget Opened new routes for purchasing equipment Budget still has small surplus to start future work Itemized financial records kept up-to-date

Current Plans: 

Current Plans Implement design plans – all finalized Final drum weapon Gearboxes Finalized hub design Instantiate radio controls – waiting on antennas Place components on frame – awaiting frame completion Shield critical components Motor controllers On-board control logic

Final Design: 

Final Design

Electrical and Controls Systems: 

Electrical and Controls Systems Led by: Jason Harris

Electrical and Control System: 

Electrical and Control System Electrical and Control teams fused Electrical design dictated by control style Team goals Design and build everything between operator and drivetrain Successfully integrate with drivetrain and weapon

Electrical System: 

Electrical System Goals achieved Hardware successfully designed and assembled Hardware operates to specification Software operates to specification Goals not achieved Radio not functional at this time due to lack of hardware

Hardware Description: 

Hardware Description Motors Two Bosch 24V 750W motors for drivetrain Continuous duty motors that draw a maximum current of 150A Easily powered by amplifiers and battery packs One Magmotor 24V 3,300W motor for weapon 3 Minute duty cycle with 550A maximum current Weapon has high angular momentum, motor uses only 4A at no-load: has only to overcome friction

Hardware Description: 

Hardware Description Batteries Two Hawker 16Ah sealed lead-acid batteries in series Low internal resistance, can source more than 300A continuously for 3 minutes Weight/Power tradeoff All amplifiers and motors optimized for use at 24V

Hardware Description: 

Hardware Description Amplifiers Five OSMC H-bridge amplifiers Can switch 160A continuous, 300A peak with little loss Protection from negative transients built in via zener diodes and Transient Voltage Suppressors 16 power nMOS transistors have individual heatsink, array is cooled by 80mm fan

Hardware Description: 

Hardware Description Controller Contains all the hardware required to accept human input, communicate via 900MHz radio, drive three motor amplifiers and provide feedback to the operator Provides 8 different voltages (5V, 3.3V, -10V, -19V, -26V, and 6VAC) to drive a wide range of hardware Onboard regulators accept 7V-40V input

Hardware Description: 

Hardware Description Controller Based on Atmel’s 8-bit ATMega128 128KB of program memory, 4KB of RAM, 4KB of nonvolatile storage and 53 input/outputs provide plenty of power 24 analog/digital inputs, 16 digital I/Os, 3 ports directly hardware compatible with amplifiers Programmable by a PC via serial interface

Electrical System: 

Electrical System Problems Controller board had layout design flaws, but they have all been worked around Radios invert transmitted signal, but was never mentioned in documentation Manufacturer late on shipping antennas Computer crash destroyed last three week’s worth of work

Drive Train: 

Drive Train Led by: Ted Kelleher

Initial Design Concerns: 

Initial Design Concerns Gear Ratios Conflicting motor specs Connecting motors to wheels and driving Gear Boxes Frame matching Redesign

Initial Frame Design: 

Initial Frame Design Problems: Did not match weapons frame Motor Mounting issues Wheel mounting Reversability Advantages: Strength Size, weight Versatility

Initial Hub Design: 

Initial Hub Design Cons: Time to machine Meshing with frame Pros: Strong Independent spinning Holding of wheel Axle integrated

New Hub/Wheel Assembly: 

New Hub/Wheel Assembly Pros: Independent Wheels Solid Axle Each assembly removable and adjustable Strength Integrated with frame Cons: Expensive bearings Multiple bearings

Overall Design And Issues: 

Overall Design And Issues Frame: Redesigned to accommodate space Reversibility, triangular shape with base See Adam Duchene Wheels and Hubs: Also redesigned, for new frame Bearings, gear boxes design New assemblies need time to build

Framing Concerns: 

Framing Concerns Led by: Adam DuChene

Initial Frame: 

Initial Frame

Final Frame: 

Final Frame

Weapon Design: 

Weapon Design Ryan Connell

Weapon Design: 

Weapon Design Goal To create a horizontally driven drum that will deliver a large impulse and destroy opponents. Components Motor Driving Mechanism Drum Axle Gripping Teeth

Motor: 

Motor MagMotor S28 Factors in Decision Performance 4 ½ hp 4500 rpm Price Electrically Powered Size 3” x 3” x 8” Weight 8 lbs.

Drum: 

Drum Purchased 6” and 8” I.D. steel piping Factors in Decision Strength Weight (approx. 20-40 lbs.) Moment (Most material farthest from axis) Material Strong Dense Weld Friendly

Driving Mechanism: 

Driving Mechanism Major Choices Available Belt Driven Allows Slipping under extreme conditions Gear Driven Limits placement of motor in final design Heavier Difficult to design/build Does not allow slipping Chain Driven Stronger Heavier Does not allow slipping

Initial Design: 

Initial Design Rotating Axle Belt Driven Drum welded to axle with steel plates Aluminum testing frame Team manufactured pillow blocks Four ½” steel bars for gripping test objects

Test Results: 

Test Results Pros Motor worked great Belt drive slipped to alleviate the motor Aluminum structure did not move from gyroscopic forces No major vibrations from unbalance Cons Batteries did not have enough power Steel bars were ineffective Slight grinding at pillow blocks

Snowmobile Studs: 

Snowmobile Studs Potential Improvement on the steel bar Designed to pierce opponents Comes in two materials Steel Carbide Tipped Steel Comes in two designs Push through Screw in

Second Iteration: 

Second Iteration Improvements Bushings added to separate drum from pillow block Spikes mounted perpendicular to outer face of drum Results Bushings worked great Spikes sheared at tip and at threaded base

Redesign of Spike Application: 

Redesign of Spike Application Problem: spikes were shearing rather than puncturing. Solution: Mounted spikes tangent to the drum to decrease shear force from attack Went to pure steel rather than carbide Using nuts rather than threading drum. This allows for versatility and easy repair.

Latest Design: 

Latest Design Three T-shaped members added to the outside of prototype drum. Upper T is for added grip should the studs shear off.

Outlook: 

Outlook Most of the final design manufacturing is finished. Waiting to get results on new teeth design. Final Design Split drum design; centrally driven Steel teeth 8” drum Modular Fixed axle

Robust and Modular Design: 

Robust and Modular Design Melody Hung

Axle and Pillow Blocks: 

Axle and Pillow Blocks Two Possible Designs Rotating Axle Fixed Axle Factors in Design Interested in being able to remove axle, should it fail. Developing a shock absorbing addition.