RP1 1kg Motor Module, First Generation P08208 – Mechanical Design P08205 – Wireless & PWM Motor Controller MSD I 20072

WHAT IS A MOTOR MODULE ? DRIVE MODULAR MOUNTING STEER aka “ MM”

kg 10kg 100kg OFF THE SHELF MOTOR MODULES

RP100 ( Wired ) RP10 ( Wired ) RP1 Sister projects! RP10 Redesign

RP10 Redesign RP1 Wireless! Robust! Autonomous! Smaller! Lighter!

ORGANIZATION BREAKDOWN P08208 Wendy Fung P08205 Reid Williamson Steer Matthew Benedict Artur Ponikiewski Drive Andrew Anderson Matthew Benedict Platform Eric Rodems Artur Ponikiewski Yoke James Edick Eric Rodems Electronics Bryan Jimenez Jonathan Maglaty Controls Brendan Hayes Philip Edwards

System-Level Process Flow Computer Wireless Receiver Microprocessor Motor Controller RP1 Motor Module

CRITICAL REQUIREMENTS Transport 1kg Payload Robust = Withstand Tabletop Drop Wireless Communication Power Motors with a PWM Signal Open Source & Open Architecture Reflect Design of the RP Family Modular Design for Multiple End Uses

EXPECTATIONS oQuantity 2, Fully Functional oSize 12in x 6in x 6in max efficiency 38 in/s oDroptest Repair Time < 5 min oWireless Range 300 ft max oBattery Life 1 hour + 1 2

FORMAT Drive & Steering Q & A Yoke & Platform Q & A Electronics & Controls Q & A DFMA & MSD II Outlook Q & A

Responsibilities: –Highly dynamic range of operating speeds –An array of different operating conditions –Robustness –Seamless system integration Risks –Difficulty obtaining different motor gearboxes –Drive Shaft Alignment (turntable wobble) –Robustness of design –Accurateness of systems modeling –Tolerances –Assembly DRIVETRAIN SYSTEM

IG 32 Motor 27:1 Gear Reduction ¼” Stainless Steel Axles ½” Aluminum Spacers 2” Diameter Wheel Axle Couplings Thrust Bearings 2:1 Synchronous Belt and Pulley Axle Collars FINAL DESIGN

SYSTEM LEVEL DESIGN

SYSTEM LEVEL DESIGN

STEERING Responsibilities: –Infinite Steering –Easy to assemble/disassemble –Robust –Seamless system integration Risks –Robustness of belt tension system –Turntable –Integration with electronics and controls –Tolerances –Assembly

IG 32 Motor 71:1 Gear Reduction ¼” Stainless Steel Axles Turntable Custom Centerpost 1:3 Synchronous Belt and Pulleys STEERING SUBSYSTEM

STEER BELT TENSION Axle Couplings Adjustable Steer Motor Mounting Plate Adjustable Bearing Plate

DRIVE & STEERING Q & A

YOKE

YOKE Responsibilities: –Responsible for structural skeleton of Rp1 –Design a rigid and robust framework –House all other sub-systems within framing –Provide protection against a 36” drop to the floor Risks –Keeping within the weight requirements –Withstand drop without any significant damage or misalignment of components –Minimizing overall cost of yoke

UPPER YOKE 1/8” AL Plate ½” x ½” Al Posts AL Angle Brackets 1/8” Al Upper Yoke to Turntable Mounting Plate Encoder standoff mounting plate 1/8” Al Motor Mounting Plates

LOWER YOKE 1/8” Al Upper Yoke to Turntable Mounting Plate 80/20 90° Base Connector 1”x1” AL 80/20 Quick Frame Mounted Flanged sleeve bearings

Design Justification Critical Decisions: –Frame built of aluminum instead of Lexan to improve strength –Used an open 80/20 fork design for lower yoke to provide maximum rigidity while minimizing weight –Used solid post box design in upper yoke to fully enclose drive, steering and electrical systems. Solid posts allows for easier hardware attachment –Turn table connected to mounting plates on both sides to support upper and lower yoke

PLATFORM Responsibilities –Platform design –Mounting of modules to platform –Idler module development –Test fixture design Risks –Design was heavily reliant on upper yoke –Design of platform for drivability

DRIVE PLATFORM 2 platforms (1 per team) –Holds 2 motor modules –Holds 2 idler modules –Square shape for adaptability

IDLER MODULE Idler Design –Past RP project experience –Use of motor module parts –Simplified design –Caster offset (slot)

TEST PLATFORM 1 test platform –Holds 1 motor module –Holds 2 idler modules –Will have quick connect adapters spec’d out from Molex

YOKE & PLATFORM Q & A

CONTROLS Graphical User Interface (GUI) –Allow the user to interact with and control the robotic platform Wireless –Responsible for the communication between the user and the platform Microprocessor –Generate control signals and monitor sensor feedback

Controls Risks –GUI User is unaware of current state of RP1 User is unable to respond quickly –Wireless Wireless interference Insufficient data rate –Microprocessor “Swamped” with encoder feedback

Final Design GUI Left Motor Module Drive Motor: Good Wheel Angle Battery Life Remaining Left Motor Module Steering Motor: Good Right Motor Module Drive Motor: Inefficiency Right Motor Module Steering Motor: Good

Wireless MIB520 USB- Gateway MICAz 2.4 GHz Wireless Transceiver

Freescale MC9S12DT256 –8 Channel PWM Module –Modular Communication IIC SPI SCI CAN Microprocessor

ELECTRONICS System Responsibilities –Provide components for motor control –Placement of motor control components –Supply power to electrical components –Confirm electrical components are compatible with microprocessor Risks –Component ratings (i.e. heat, amps, etc.) –Lead time on final part selections –Compatibility between electrical components

Final Design H-bridge –PWM Motor Controller 3A Encoders –US Digital EM5 EM1 HUBDISK

Final Design Power Schematic for encoders (5V)

Final Design Simulation for Encoder Power Schematic

Final Design Battery Selection –NiMH –24V –3.5Ah –Rechargeable

CONTROLS & ELECTRONICS Q & A

Design For Manf. & Assembly Steering assembly implementation Degree of machining precision Bending of motor shaft Spacing and fasteners Control Communication Functional control

Plans for MSD II Build RP1 prototype Test accuracy of system modeling Build test fixture Do the drop test Look into possible aesthetical improvements Optimize current design Build GUI Setup basic wireless communication Test all electrical components Full system integration and test