Autonomous Explorer Group 6 Michael Jun, Scott Hewson, Braedan - PowerPoint PPT Presentation

Autonomous Explorer Group 6 Michael Jun, Scott Hewson, Braedan Jongerius

Our Project Build an autonomous robot that will avoid obstacles and build a 2D map of its environment.

Robot Platform Rover 5 ● 4 motors with encoders ● Adjustable ride height ● Motor rated voltage: 7.2V ● Motor stall current: 2.5A ● Output shaft stall torque: 10Kg/cm ● Gearbox ratio: 86.8:1 ● Speed: 1Km/hr

Optical Encoders ● 1000 state changes per 3 wheel rotations ● A and B XOR-ed together for interrupt ● 5V dropped to 3.3V with voltage divider

Ultrasonic Rangefinders Maxbotix LV-EZ4 ● 42kHz Ultrasonic sensor ● Low 2mA supply current ● 20Hz reading rate ● Analog Output - 10mV/inch ● 6 to 254 inches (6.45m)

Digital compass Honeywell HMC6352 ● Simple I2C interface ● 1 to 20Hz selectable update rate ● 0.5 degree heading resolution ● 1 degree repeatability

Hardware Diagram Range Finders Optical Encoders 5 1 8 ADC XOR 4 DE0 Nano Motor PWM 4 Pairs Voltage 4 Counters Divider I2C 1 1 Compass

Sensors Layout

Software

Scalar to Vector Conversion if(Command==NOT_TURNING) { CarPositionX= cos((Angle+90)*PI/180)*DistanceTraveled+CarPositionX; CarPositionY=sin((Angle+90)*PI/180)*DistanceTraveled+CarPostionY; } LeftSensorX=cos((Angle+180)*PI/180)*LeftSensorScalar+CarPositionX; LeftSensorY=sin((Angle+180)*PI/180)*LeftSensorScalar+CarPositionY; RightSensorX=cos((angles)*PI/180)*RightSensorScalar+CarPositionX; RightSensorY=sin((angle)*PI/180)*RightSensorScalar+CarPositionY;

Test Plans ● Simulate inputs to test VHDL components ● Measure outputs from sensors to verify function ● Measure current draw from components ● Have robot navigate simple obstacles

The Future of the Project ● SD card storage / wireless transmitting ● Backtracking and/or nodes ● Improved turning algorithms

The Current Challenges ● Rangefinder can't sense < 6 inches ● Rangefinder beam pattern ● Current draw ● Retrieving and displaying mapped data in a simple manner

Questions?