Instruction Guide: EV3 - Turning
In this Lesson we have 1 Primary Instruction Resources::
- The resource is a EV3 Trainer lesson on Turning.
The EV3 Trainer Teacher's Guide references this on pages 31-35.
Additonal Assessments are discuseed at the end of this Guide.
Resource 1:
This lesson covers using the Move Steering block and the Move Tank block to control robot turning.
The students will return to the EV3 Trainer and work their way thru the Turning section.
Students should be able to use both Move blocks and understand the differences between the two.
Have students work thru:
The EV3 Trainer:
Behaviors > Movement > 2. Turning 1-5, C
The EV3 Trainer Teacher's Guide references this on pages 31-35.
Students should be able to answer the questions at the end of each section and complete the challenges. Have students work thru and complete the EV3 Turning Task Assignment Sheet.
The EV3 Trainer Teacher’s Guide has additional reproducibles for those who have purchased the product. The reproducibles for Turning can be found on page 96.
The challenges:
Turning Challenges (Task Assingment Sheet)
Turning 90 degrees - Behaviors > Movement > 2. Turning 3
Dizzy Drills - Behaviors > Movement > 2. Turning 4
Orchard Challenge - Behaviors > Movement > 2. Turning Challenge
- In the Orchard Challenge, using pseudocode,have students describe how they tackled the problem:
- How did they break down the challenge?
- How did they approach each piece?
- What techniques did they use:
- Guess and check only?
- Port View App to determine the number of rotations for a given maneuver?
- Reuse program pieces that were repeated?
- Use proportions to scale turns and distances?
- Repeatability is a struggle with plastic robots.
- Factors which effect repeatability include:
- Initial orientation of tribot - x,y position and rotation
- Slack in drive train (motors, gears wheels)
- Wheel alignment Wheel balance (wobble)
- Structural rigidity
- Uneven friction
- Mismatched motors
- Battery level
- Motor control (Move & Motor Blocks)
- Factors which effect repeatability include:
- Have students share their different approaches so everyone can see how one problem can have many solutions and how other techniques can be used to reduce the tedious guess-and-check method.
- Discuss why this challenge was so difficult (tedious) and introduce the idea of odometry for navigation versus using sensors to help determine position during navigation. With odometry, you only know your position at the very beginning and each error or variation compounds on the previous errors or variations.
Beyond the Orchard Challenge built into the EV3 Trainer Turning lesson, the following challenges allow students to hone their turning skills.
Don't forget to page down below the challenges to Optional Activities and Did You Notice?.
Additonal Assessments:
NOTE: It is recommended that students do The Flashlight Follower under Additional Assessments. Examples in the subsequent Flow Charts Lesson 3 will be based on this program.
This Extended Additonal Assessment is a more open-ended challenge that combines the new turning skills with prior learning about the light sensor. Students need to create a robot that will follow a flashlight beam through a lengthy course involving turns in both directions. (Note: the robot must follow the flashlight beam, not just respond (e.g. turn) when the light is shined on it or it hears a sound, etc.)
In addition to the above items, some key learning to watch for is:
- Writing a program that repeats the same behavior over and over creates a very long program when done with cut-and-paste - students may discover (or you may want to introduce) the infinite loop to repeat a set of commands
- Reliability and precision of the follower will improve by following the beam on the ground rather than in the air
- This is an application where the light sensor may work better with the LED turned off (ambient light mode) - this creates a larger contrast between beam and no-beam
- There will be a trade-off between speed of the robot and ease of control - students will need to find the optimal balance for the minimum time through the course
This Alternative Additonal Assessment is borrowed from the NXT version of the course.
