ECE 477 Design Review Team 14  Spring 2011 Paste a photo of team members here, annotated with names of team members. Jinliang Wei, Kelton Stefan, Ankith Cherala, Seongwoon Ko

Outline Project overviewProject overview Project-specific success criteriaProject-specific success criteria Block diagramBlock diagram Component selection rationaleComponent selection rationale Packaging designPackaging design Schematic and theory of operationSchematic and theory of operation PCB layoutPCB layout Software design/development statusSoftware design/development status Project completion timelineProject completion timeline Questions / discussionQuestions / discussion

Project Overview Self-balancing Biped Robot is a robot that performs basic functionalities of human legs, such as moving and changing directions. While utilizing 4 servos on each leg during motion, our robot would receive instructions from a controlling software (GUI) using wireless communication. The goal of this project is to modify and use a pair of robotic legs to achieve desired motion.Self-balancing Biped Robot is a robot that performs basic functionalities of human legs, such as moving and changing directions. While utilizing 4 servos on each leg during motion, our robot would receive instructions from a controlling software (GUI) using wireless communication. The goal of this project is to modify and use a pair of robotic legs to achieve desired motion.

Project-Specific Success Criteria An ability for the robot to balance itselfAn ability for the robot to balance itself An ability for the robot to walk forwardAn ability for the robot to walk forward An ability for the robot to “pivot”An ability for the robot to “pivot” An ability for the robot to detect an obstacle in its forward path and “halt”An ability for the robot to detect an obstacle in its forward path and “halt” An ability to remotely control the robot’s operating modeAn ability to remotely control the robot’s operating mode

Block Diagram

Component Selection Rationale Major Components: Major Components: 1.Microcontroller. 2.Wify Module.

Microcontroller Selection CategoryMC9S12A512AT89C51RE2 RAM14 KB8 KB Flash memory512KB128 KB Clock speed25MHZ60 MHz Data bus16 bit8 bit

Wireless Module Selection Comparison BasisXBee 1mW Chip WiFly GSX b/g Serial Module Micro-controller interfaceSCI Need PC counterpartYesNo PC counterpart interfaceUSB explorer boardN/A NetworkZigbeeWifi ConfigurationMicro-controllerPC Telnet support Cost$70.85$49.95

Packaging Design General Specifications: CategoryDescription Height10.2 inches Width6.5 inches Ground Clearance2.5 inches Weight (Without Batteries or payload) oz. Range of Motion per joint180 o

Major Components On The Frame PartQtyLocation Hitec Servo Motors – HS on each side of the hip, 1 on each knee, 1 on each ankle. Dimensions: (41mm x 20mm x 37mm) Weight: (45.5/1.6) g/oz. Battery Pack1 LiFePO4 Battery placed on the torso in front of the PCB in a U shaped 4 inch long aluminum channel. U-Shaped Aluminum Channel1Placed on the torso towards the anterior (front side). C-Shaped Brackets14All over the leg linking each segment. Different sizes used. Aluminum Robot foot pair2Base of the robot on which the ankle servo motor is placed. Circuit board + Microcontroller1Placed towards the posterior (rear side) of the torso.

Dimensions ComponentsDimensionsWeight (in gms) ASB09 - C bracket51mm x 25mm x 40mm17.5 ASB-04 - Servo Bracket57mm x 25mm x 35mm17.5 ASB06 - L bracket36mm x 25mm x 29mm1.05 ASB Aluminum Channel - 3"76.2mm x 25mm x 25mm31 Foot63.5mm x mm29 Servo41mm x 20mm x 37mm46 Battery pack73mm x 18mm x 76mm172

Positive Aspects of Packaging The robot can turn to the side without walking.The robot can turn to the side without walking. PCB assures connection to various components while fitting in a compact area.PCB assures connection to various components while fitting in a compact area. Wide robot’s foot would help in maintaining stability.Wide robot’s foot would help in maintaining stability. PCB is shielded.PCB is shielded. PCB is fixed to the U-shaped aluminum channel.PCB is fixed to the U-shaped aluminum channel.

PCB layout ComponentLength (mm)Width (mm)NumberComments MC9S12A WiFly card37201 Hang over length: 8 mm(included) Logic Level Converter V power regulator NCP Servo PWM pin connectors18 1 BDM connector1051 Status LEDs205 Controller pin connector189 PCB dimension8852

Front View

Side View

Top View

Isometric View

Micro-Controller

Oscillator Circuitry

BDM

WiFly Card

Accelerometer

Theory of Operation Hardware Design ObjectivesHardware Design Objectives –Generating 8 different duty cycles, which would control angular position of each servo. –Integrating all other components with the micro controller. –Configuring the modes of the subsystems for each component

Theory of Operation MicroprocessorMicroprocessor –MC9S12A512 –Will be run at 5 MHz using 5.0V PowerPower –12.8V LiFePO4 battery pack –5V switching regulator x 2 Pololu D24V6ALVPololu D24V6ALV Pololu D15V70F5S3Pololu D15V70F5S3 –3.3V linear regulator STMICROELECTRONICS - LD1117S33TRSTMICROELECTRONICS - LD1117S33TR

Theory of Operation Servo motors - Hitech hc422Servo motors - Hitech hc422 –Controlled with PWM on microprocessor Wifi module - WiFly RN-131GWifi module - WiFly RN-131G –Ad-hoc Network, b/g 3-axis accelerometer - Bosch BMA1803-axis accelerometer - Bosch BMA180 –Measures between 0-2G Ultrasonic range finder - Maxbotix LV-EZ2Ultrasonic range finder - Maxbotix LV-EZ2 –Finds objects from 6in. to 254in.

PCB Considerations SizingSizing Three different voltages – 12.8VDC (unreg), 5VDC (reg), 3.3VDC(reg).Three different voltages – 12.8VDC (unreg), 5VDC (reg), 3.3VDC(reg). Servo motor induced power noise.Servo motor induced power noise. Servo current draw.Servo current draw. Signal integrity of servo motor control.Signal integrity of servo motor control. Microcontroller (oscillator, bypass caps)Microcontroller (oscillator, bypass caps) RF interference with WiFi radio.RF interference with WiFi radio.

Size 110x70mm110x70mm –(110mm = width of robot hips, 70mm = height of battery pack) 110mm 70mm

Voltages & Servo Noise Due to concern s over servos creating noise on supply, will implement two 5v SMP supplies.Due to concern s over servos creating noise on supply, will implement two 5v SMP supplies. Servo Supply Supply for Everything Else

Servo Current & Signal Integrity Servo header between MCU and SMP SupplyServo header between MCU and SMP Supply Power Supply MCU

Microcontroller Oscillator CircuitOscillator Circuit

Microcontroller Bypaass Capacitors PLL External Components

WiFi RF Interference WiFi and SMP supply separatedWiFi and SMP supply separated

More Details  Bulk Capacitors 5v3.3v

Micro-Controller

Accelerometer

WiFi

12.8V Traces

Main - GND Traces

Servo 5V Traces

Servo GND Traces

Main – 5V Traces

Main – 3.3V Traces

MCU WiFi LEDs

BDM and Reset

Wi-Fi Ad-Hoc Select

Range Sensor Header

WiFi SCISCI Logic Level Converter Test Points Power Test Points 8 GPIO + I2C 4 Timer Channels Other (debugging) Headers

Software Design Programming Language UsedProgramming Language Used –Microprocessor : Embedded C –Simulation : Matlab –GUI : C++ ComplierComplier –Motorola HC/HCS12

Development Status MatlabMatlab –Kinematic & Inverse Kinematic –Newton’s Method for square root approximation Embedded CEmbedded C –Initializations –PWM in conjunction with TIM module –Look up tables

Project Completion Timeline Week 8 PCB completed; All parts ordered. Week 9 PCB verification; Proof of parts; Start using WiFly card; Look at research papers to figure out biped robot motion Week 10 – Spring Break Week 11 PCB tested block by block; Start PC side GUI design; Wireless communication set up; Robot is able to walk and balance Week 12 PC side GUI done; Robot is able to turn Week 13 Robot autonomous navigation Week 14 – Test and margin for errors Week 15 – Test and margin for errors

Questions / Discussion