GPS Robot Navigation Critical Design ReviewNeedGoal and ObjectivesLitteratureDesign ContraintsAlternative SolutionsSlide 7Final Design BreakdownSlide 9SubsystemsObject DetectionSRF04 Controller InterfaceSRF04 AlgorithmSlide 14Velocity ControlOptical EncoderVelocity Control (cont.)Navigation SystemSlide 19Validation and Testing ProceduresScheduleDivision of Labor and ResponsibilitiesEconomic AnalysisSocietal, Safety, and Environmental AnalysisGPS Robot NavigationCritical Design ReviewChris Foley, Kris Horn, Richard Neil Pittman, Michael WillisNeedUnmanned and automated systemsCan protect human livesCan provide convenience and safetyMilitaryWarfareDangerous locations SurveillanceCivilianEveryday navigationGoal and ObjectivesGoal: Develop a GPS guided system that will successfully navigate to a series of pre-defined coordinates.Objectives:Stable, sturdy systemAble to start at any locationFollow a pre-defined pathBe able to avoid obstaclesLitteraturewww.oopic.comwww.junun.org/MarkIIIThe Devantech SRF04 Ultrasonic Range FinderOptical EC Encoder Kit DocumentationDesign ContraintsBudgetTimeTechnical ScopeAlternative SolutionsCompass or not ?Reprogram using a laptop, or a keypad ?Control the car by tapping into the servos or by using the remote control circuit ?Final Design BreakdownMark III Board with OOPic provides controlSonar Configuration provides obstacle detectionGPS and Compass provide navigation informationFinal Design BreakdownUser interface through serial connection to computerLCD provides user feedbackBattery and voltage regulation provide power to componentsSubsystemsObject Detection SystemVelocity Control SystemNavigation SystemObject DetectionSonar:-- Efficient outdoors-- Far rangeDevantech SRF04 Ultrasonic range finder.Range 3” – 10’SRF04 Controller Interface4 pins: Power, Ground, input Trigger, and output Echo.Trigger 0→1: Sonar emits a ping and the Echo → 1.Echo → 0 ping returned.SRF04 AlgorithmTime length Echo is high.Sea level sound travels 2’/1.8 mSec.Obj. Distance ft. = (time sec.) * (1/.0018)Sonar ConfigurationVelocity ControlManual speed controlServo controls motor voltage.Optical Encoder measure angular velocity.Optical EncoderE3 optical encoder US Digital Corp.3 output channels A, B, and Index used read quadrature track.A leads B, rotating CW. B leads A, rotating CCW.Index: 1 pulse / rev.Velocity Control (cont.)Navigation SystemInputs: destination coordinates, current GPS coordinates, compass heading, steering commands (from collision avoidance system)Outputs: steering control commands, speed control commands, coordinate readingNavigation SystemFunction: control the movement of the robot along a pathUses algorithm programmed into the OOPic to make path calculations based on current inputsWill always choose best path from current locationValidation and Testing ProceduresTest individual components(speed control, steering, sonar, lcd, gps, compass, navigation algorithm)Integrate and test piece by pieceTest system as a wholeScheduleDivision of Labor and ResponsibilitiesThe GPS unit and Navigation Algorithm: Chris and Michael Compass, Sonar and Servos: Kris and NeilEconomic AnalysisEconomical ViabilityTotal cost per unit: $352.50SustainabilityComponents from various vendorsManufacturabilityFCC compliant GPSProduction yield dependant on number of workersSocietal, Safety, and Environmental AnalysisUse the robot for locations that are unsafe for humans or difficult to get to.Exhibit normal care and safety measures that apply when using electronic equipmentCarefully plan path so as not to harm
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