1. Autonomous Rover A Path Following and Obstacle Avoidance Vehicle RIT Computer Engineering Senior Design Project Bryan Allen and Jonathan Wyant Thursday, February 10, 2005 Inspiration: This project is a prototype for a naval autopilot system. The proposed system would guide naval vessels in and out of harbors avoiding traffic and shallow areas. Description: The autonomous rover is a self-contained path following and obstacle avoidance vehicle. It will traverse a path defined by red and green tape and avoid obstacles within the path without going outside path boundaries. No input is required from the user other than turning the system on or off. Implementation: The system utilizes an Infra-red Sensor Network to view the environment around it. The sensor network can cover roughly a 180 degree arc 6-10 inches away from the vehicle. The sensor arc is divided into sectors. Each sector represents a different path that the rover can take when it needs to avoid an obstacle. As long as one sector is free, the rover will continue to operate. Figure 1: Autonomous Rover on PathFigure 2: Autonomous Rover – Front View Light-to-Voltage sensors are used for path boundary detection. If a path boundary was encountered, it will not be possible for the rover to move back in the direction of the boundary for the next 3 seconds. Sector 1 Sector 3 Sector 5 Sector 2 Rover Sector 4 IR1IR2 IR3IR4 IR6IR5 IR8IR7 In this situation we assume we just hit the Green Path Edge, meaning we cannot go to the right. This blocks Sector 3 and Sector 5. There is an obstacle in front of us that we have to avoid. This blocks Sector 1. There is an obstacle blocking Sector 4. The only free sector we can turn to is Sector 2. So the rover will turn so that it is facing Sector 2 and proceed forward. Sector 1 Sector 3 Sector 5 Sector 2 Rover Sector 4 IR1 IR2 IR3 IR4 IR6 IR5 IR8 IR7 Obstacle Cost Breakdown DescriptionVendorUnit CostUnitsOur CostTotal Cost Acroname Brainstem GP 1.0Acroname79.001 TAOS TSLX257 LTV SensorsTAOS, Inc.6.744Free Samples 26.96 Sharp GP2D15 IR Sensors w/ CableAcroname11.50892.00 Sheet of Material (Lexan)Niagara Hobby & Craft Mart17.591 Battery Pack w/ ConnectorAcroname3.5027.00 Colored Duct TapeJo-Ann Ect.4.29417.16 4Pk AAA Battery CaseRadio Shack1.891 ICB86 PC BoardsRadio Shack1.7935.37 LM341T-0.5 Voltage Regulator (+5V)DigiKey0.821 4Pk AAA Batteries (Energizer E2 Lithium)BestBuy11.991 4Pk AA Batteries (Energizer E2 Lithium)BestBuy12.99225.98 Serial Interface ConnectorAcroname10.001 Black Wheels with Black BandsAcroname2.50410.00 Standard Servo w/cont, BBAcroname21.00484.00 IC Socket (16pin)Radio Shack1.291 Wiring (22 Guage)Radio Shack4.291 35 Crimps and HousingsAcroname11.00222.00 Servo Motor Mount BracketsReynolds Electronics5.75211.50 Heat SinkRadio Shack1.691 Heat Sink Mounting HardwareRadio Shack1.691 Servo EncoderAcroname32.951 PermaMount TapeRadio Shack1.9923.98 Two-Way Toggle SwitchRadio Shack2.991 SN74LS257BN MultiplexerDigiKey0.721On Hand0.72 Lego BlocksVarious KitsN/A DM74LS02N NOR GatesDigiKey0.532On Hand1.06 Red LEDsDigiKey0.075On Hand0.35 100 Flat Lego 2x2 SquaresLego@Home6.991 Grand Total (less tax, s/h) $452.27$481.46 Figure 3: System Block Diagram illustrating the relationship between different layers of processing and control. Bryan Allen Jonathan Wyant Figure 4: Sector Definitions and IR Sensor Placements Figure 6: Algorithm Example Figure 5: LTV Mounting Housings Figure 7:Hardware Schematic Figure 8: TEA VM Software Flowcharts Figure 8: Project Cost Breakdown Acroname’s Brainstem GP 1.0 Texas Advanced OptoElectronic’s LTV Sensors Sharp’s GP2D15 Digital IR Sensors Acroname’s Continuous Rotation Servo Motors Special Thanks to Mark Whitney from Acroname, Inc.