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Topics Covered

  • Turning

    • Lesson Links

    ... ...
    Check Your Understanding:
    1. 1. What does the robot do when the TurnRight program is run?
      2. Move straight forward
      Spin to the right without moving forward at all
      Lock the right wheel in place and run the left wheel forward
      Turn the robot completely around 1 time
    2. 2. True or False: With "Rotations" on the TurnRight Command Block to 1, the whole robot rotates 1 time.
      3. True: the robot will turn around 1 time
      False: the wheels will turn 1 time, not the body
    Try It!
    Try it! 1

    Direction of Turn

    Using the turnRight command block makes the robot turn to the right, in place. What happens if you use the turnLeft command instead? Try it!
    Virtual Robot DirectionOfTurnVR.rbg Physical Robot DirectionOfTurn.rbg

    What happens?
    The robot turns in place to the left!
    1. 1. How much did the robot's wheel turn during this movement?
      2. 1 rotation
      1 degree
      Enough to make the robot spin completely around one time
      One lap around the table
    2. 2. What does the "1 rotation" refer to in the turnLeft Command Block controls?
      3. 1 full rotation of the robot's body during a turn
      1 rotation of the robot's wheels
      1 time that the robot is picked up and turned around
      One rotation of the Earth around its axis
    Try it! 2

    Units of Turn

    What happens if you switch the second box of the turnLeft or turnRight command from Rotations to Degrees? Try it!
    Virtual Robot UnitsOfTurnVR.rbg Physical Robot UnitsOfTurn.rbg

    What happens?
    The robot barely moves when it’s set to move 1 Degree! There are 360 degrees in one rotation of the motor, so it barely moves.
    From the change you made above, change the value in the first box from 1 to 270. Try it!

    What happens?
    The motors turn ¾ of a rotation, making the robot turn much further.
    Using degrees as your units gives you greater control over the robots turns!
    1. 1. How much did the robot's wheel turn during this movement?
      2. 270 rotations
      2.7 rotations
      3/4 of a rotation
      It didn't move
    2. 2. Why would you use Degrees instead of Rotations?
      3. If you are turning in reverse
      If you're using a temperature sensor to control movement
      For greater control over the robot's turns
      You wouldn't
    Mini Challenge

    Mini Challenge 1: 90 Degree Turn Challenge

    Program your robot to turn exactly 90 degrees to its right!
    Virtual Robot 90DegreeChallengeVR.rbg Physical Robot 90DegreeChallenge.rbg
    • Place two pieces of tape so they form 90 degree angles.
    • Place your robot so it faces along one piece of tape, and program it so that it turns to face directly along the next piece.

    Change the amount your robot turns by changing the number of Rotations it is programmed to go.

    Measure how far your robot turned with its 1 rotation program, and see if you can use that information to reason about how many rotations is should take to turn 90 degrees instead!

    + hint
    Mini Challenge

    Mini Challenge 2: Dizzy Drill

    Program your robot to run out to an obstacle, go around it, then come back.
    Virtual Robot DizzyDrillVR.rbg Physical Robot DizzyDrill.rbg

    You may use any kind of turn you want to complete this maneuver.

    + hint
    Did You Notice?

    Did you notice?

    Wheel Pointers

    The white pointers on the EV3's tires help you to see how much the wheels are rotating.

     

     

     

     

     

    Run your TurnLeftprogram again,
    and watch the pointer on the robot's right wheel

     

     

    Did you notice?

    Wheels and Turning
    All your robot's movement is based on the way in which its two motors move.
    The motion you get is determined by using different combinations of powers on those motors.
    If both motors go forward, the robot moves straight forward.
    If both motors run backward, the robot moves straight backward.
    If they run in opposite directions, they robot spins in place.
    If the left side moves forward while the right moves back, the robot spins to the right.
    If the right side moves forward while the left moves back, the robot spins to the left.
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    Copyright(c)2012 Carnegie Mellon Robotics Academy. All rights reserved.