Robot

Robot

1. Task Requirements

   • Prescribed Criteria
     • Follow the path using a line following algorithm
       • Use colour sensor to navigate around the map/detect the line
       • Robot must be indefinitely checking for line, adjusting when needed.
       • Robot must be able to turn left and right
       • Robot must be able to detect colour black or reflection below _%
     • Detect and navigate around/move the obstacle using appropriate sensor/s on the Spike Prime
       • Robot must detect whether Ultrasonic Distance < 5cm
       • Robot must be able to repeatedly turn and move forward to get around the obstacle
       • Robot must increase speed to push obstacle off path
       • Robot must be able to resume line-following code
   • Self Determined Criteria
     • Celebrate finishing the course and moving obstacles
       • Audible
         • Play a pre-recorded sound track or create a tune with the pitch blocks
       • Visual
         • Display happy face and/or joyous remark on 5x5 LED Matrix
         • Spin in circles
         • Move forward and back twice in rapid successsion
     • Utilise Intersection markers to avoid path breaks
       • Colour Sensor input determines which direction to turn
   • Constraints and Limitations
     • Coding Environment
       • Rowdy
       • Congested
       • Distracting
     • Skills
       • Transfer of EV3 knowledge to Spike Primes
       • Combining line following and obstacle detecting algorithm into one code
     • Time
       • 3 hours maximum of allocated coding time per week
       • 5 weeks total for constructing report, developing code and evaluating
   • Existing Solutions
     • One Sensor Line-Following Algorithm
       • Set one motor to run at a slight decrease or increase in speed so that the robot favours one direction (the direction toward the line). When the sensor sees the line, the motor closest to the line speeds up briefly to keep if from crossing.
         • Pros
           • Simple circuit
           • Easy to program
           • Does the job at a minimal level
         • Cons
           • Only works well in a straight line (no abrupt turns)
           • Time is wasted travelling the extra distance
           • Cannot operate at high speeds

2. Spike Prime Robots

   • Software Available
     • LEGO Education
       • Spike Prime
       • Spike Essential
     • LEGO Mindstorms
   • Motors
     • Technic Large Angular Motor
       • Operates in rotations, degrees or seconds
       • 250mm Wire Length
       • Voltage Range
         • Min: 5V
         • Max: 9V
       • No Load
         • Torque: 0Ncm
         • Speed: 175 RPM +/- 15%
       • Maximum Efficiency
         • Torque: 8Ncm
         • Speed: 135 RPM +/- 15%
   • Sensors
     • Gyroscope
       • Detects changes in orientation and rotation
     • Ultrasonic
       • Determines proximity of objects by measuring the time between emission and reception of ultrasonic waves
       • Gives value in centimetres or inches. Useful for navigating around spaces
     • Colour/Light
       • Determines colour values by sensing reflection of light
       • Useful for line-following
     • Touch
       • Determines whether the robot has been obstructed by an obstacle
       • Detects whether the button is pressed or released
   • Constrains/Limitations
     • Sensor Placement
       • Touch sensor is positioned on top of the robot meaning it may run into the wall though not sense it due to the floor ledge keeping the base of the robot away
       • Objects beneath the fixed ultrasonic sensor will go unsensed
     • Input Delay
       • Delay in the colour sensor may cause the robot to miss the line and rotate backwards or fail to stay on the line during sharp turns due to adjusting late
       • Delay in the ultrasonic sensor may cause the robot to hit obstacles or fail to navigate around them
     • Single Colour Sensor
       • A more practical and efficient two-sensor line following approach is unfeasible as a result

3. Developer Problem

   • Coding Environment
     • Development Tools
       • Introduction to drag-and-drop block coding
         • Scratch
         • Code.org
     • Key Algorithms
       • Line Following
       • Obstacle Detection

4. Task Analysis

   • Rules
     • Start at either green location (but do not have to return to one)
       • Set timer for ending program
       • If (obstacle moved/avoided) do ‘celebration’ and end program
       • If (red detected) end program
     • Whole course does not need to be completed, though Prescribed Criteria must be demonstrated
       • See Prescribed Criteria
     • Must use Spike Primes
       • See Spike Prime Robots
       • No modifications allowed
     • Obstacle is an empty Robot Storage Box
       • Detectable with ultrasonic sensor
     • Location of obstacle can be changed
       • Obstacle detecting code must be adaptable to any situation/location
         • Use of ultrasonic sensor as opposed to calculated movements around obstacles
         • If (obstacle detected) then (perform function) else (resume line following code)
       • Detection algorithm must always be running
         • Forever loop
   • Possible Solutions/Ideas
     • Line Following
       • Code Samples
     • Obstacle Detection
       • Code Samples
   • Coding Constructs
     • Sensors
       • Ultrasonic
       • Colour
     • Control
       • Repeat Until
       • Forever loop
       • If Else

5. Available Resources

   • QLearn
     • Information on Spike Primes and assignment
       • Algorithms, flowcharts and pseudocode explanations and tutorials
       • List of criteria to meet
       • Basics of coding with EV3/Spike Robots
   • Spike Prime
     • Programming Software
       • Runs code to complete challenge
     • Website
       • In depth tutorials on how to use software and robot
   • Youtube
     • Inspiration and tutorials for coding