P11017: Tactile Navigation Interface

P11017: Tactile Navigation InterfaceChristian SeemayerRob ProettiTim DeBellisTim GiguereWill KellyDesign Review Outstanding IssuesHow does the device tactile perception become affected due to device and strap sensations?Orientation of Servos as a perfect diamondStress AnalysisHousing displacement should allow translationServo-Arm stress due to Servo stall torqueFatigue AnalysisEndurance Limit for AluminumElectrical Analysis concernsPCB board with test points at all nodesSize of PCB traces depending on current45 angles for PC trace cornersBattery Life based on % used during dayUse of keypad interrupts instead of pollingHeat Generation from internal componentsTest Plan updatesMSD II schedule changes

Device and Strap Sensation EffectsMeeting at ABVI on 2/18/2010 with Alexis Read and Richard What we discussedRetested more tip designs out of curiosity with preference being large bowl shape (Screw head) Concept of generating diagonal directions through pulsingDirectional Testing (2 Tests)Basic TestArmband and weight applied Test

What We LearnedResults: 100% accuracy from participants. Extra sensations demonstrated no effect on accurate direction interpretation. Direction recognition training quicker then expected.Short (~1 minute)training period Proper Training approach Diamond Construction Participants disliked diagonal direction idea4 directions good, 8 creates confusion.Revamped analysis based on recommendations from Design Review Put tiny clear dots on the buttons (For sale in Vision Shop at ABVI, 6 dots for $2)

Tip Redesign after ABVI visitSwitch from sharp point to more circular area.AdvantagesMore blunt surface Enables more pressure on skinLarger surface makes it more perceptible to user

Adjustment of Servo OrientationServos oriented to create perfect diamondRequired pegs to be different lengths

Stress Analysis: HousingDevice HousingSwitched boundary condition from All DOF to fixed displacement in load directionAccounted for translation that can occur.Servo-ArmAccounted for servo stall torque

New Housing StressIn the Bottom: 482 psi

Servo-Arm Stress AnalysisIgnoring Stress ConcentrationStress of 6,637 psiDeflection of 5.775e-3 inches

Servo-Arm Hand Calculations

Fatigue Analysis

PCB Board Re-design

Battery Life Analysis

Motor Control Circuitry Analysis

Motor Control Circuitry Analysis

Motor Control Circuitry Analysis

Motor Control Circuitry Analysis

Servo Control Schematic

MCU/Power Unit Schematic

Team Interfacing DataCompletely new documentReview posted document on EDGE under Miscellaneous Documents

Heat Generation EffectsTest Plan UpdatesListed engineering specifications correlated to each testCan be found under test description and on Specs PageAddition of Test #3 Electronic Component TestingAims to test individual components to ensure proper functioning before beginning assembly periodEliminated Destructive Tests (Device Drop and Compression)Moved up test dates in scheduleRearranged testing order to account for test with similaritiesDirection Relay Test to be conducted with Servo Positioning TestOn/Off Switch Test to be conducted in Week 2 or 3 based upon assembly

MSD II UpdatesTest Plan Date updates incorporated directly into scheduleCreated a more specific focus on machining of componentsCreated a focus toward part assembly times for both mechanical and electrical componentsRough Draft of paper to be started Week 375% complete by Week 8Final draft by Week 9Rough Draft of Poster constructed for Imagine RITTo be finalized during Week 10Project Plan for MSD I has helped define each members role within the team and establish reasonable goals

Evolution of Overall Project PlanDriven to focus on customer needsCreated specific and sometimes last minute alterationsAltered to account for switches in project designAccounted for simplification of overall project goalDevice becoming stand alone with self inputs

Risk Assessment UpdatesThermal EffectsElectronic components fail to workPCB does not act with circuitCircuit does not match PCBOutside tactile sensation impede user perception of directionsSystem noise distorts system signalsFinal BOM

Where do we go now?At ABVI meeting, design was discussed to ensure customer needs were still satisfiedAll standing issues have been reanalyzed in the presentationDesign subsystems were reviewed and updated as a resultCurrently all documentation is available on EDGEFrom the BOMWhat is available here at RIT and where?What do we have to order?Non-issuesSmall lead times for parts (1 week is maximum)Testing can begin as soon as components gatheredCurrent cost is far below $1,500 budget, currently only $428.31Is the project a Green Light?If yes, when can we begin ordering?