Instruction Guide: EV3 - "Moving Straight"
In this Lesson we have 2 Primary Instruction Resources:
- The 1st resource is a EV3 Trainer section on Moving Straight.
- The 2nd resource is from the EV3 Programming Overview for FLL Coaches.
Resource 1:
The EV3 Trainer has a section describing Movement.
The EV3 Trainer Teacher's Guide references this on pages 21 to 28.
Behaviors > Movement
- Moving Straight 1 - Real world example of robot doing repetitive activities
- Moving Straight 2 - Robot build for the challenge at the end of the lesson
- Moving Straight 3 - Moving at its most basic, has mini challenge
- Moving Straight 4 - Moving an arm up and down, has mini challenge
- Moving Straight 5 - Allows students to click on blocks and have that block explained in detail
Students should be able to answer all the review questions at the end of each step and end up with a solid command of each parameter in the Move block configuration panel (except the Steering control). Students should be able to complete all Challenges.
The Optional Activities below the review questions in Step 3 include several "Did You Notice" items which review various aspects of the EV3 system.
"Try It" sections which dig deeper into the Move Block paramters are also availalbe below the review questions in Steps 3 & 4.
The EV3 Trainer Teacher’s Guide has additional reproducibles for those who have purchased the product. The reproducibles for Moving Straight can be found on pages 93-94.
Have students work through the self-paced lesson Moving Straight lessons from the Behaviors page in EV3 Trainer.
- The students will need to find the EV3 Trainer icon on their desktop and click on this icon.
- Have students do the recommended robot build.
- Have the students press the number keys (1-5 and C) to progress thru the videos. 'C' is the Challenge.
- Have students complete the mini challenges in videos 3 and 4.
- Have students complete the challlenge (C).
As students progress through, have them document their milestones in the Moving Straight Task Assignment Sheet..
Resource 2:
Another useful resource is these Move Steering Block pages exerpted from the EV3 Programming Overview for FLL Coaches
The key points are:
The Move Steering Block Port Selector control (upper right hand corner) identifies the Ports to which the motors are connected.
- Note: When two ports are selected, the Move Steering Command attempts to synchronize the paired-motors
- If one motor slows or stops, the other will try to match
- Ports B & C are the default matched motors in EV3-G
- Both motors move either forward (positive power) or backward (negative Power)
- Allows steering by applying more power to one of the two motors.
The Move Steering Block Mode Selector allows the student to select what they want the motor to do.
- X is STOP
- The circle is ON and there are some options for ON including:
- ON (stay on until told to turn off by another block or the end of the program)
- ON for seconds
- ON for a certain number of degrees
- ON for a certain number of rotations.
The Move Steering Block Power control sets the power level applied to the motors.
- A postive number is move forward.
- A negative number is move backwards.
- Note: This is not a speed control. The power setting effect on speed is non-linear and a function of battery level, output load, and operating conditions.
- Note: small amounts of power may cause the robot to stall.
The Move Steering Block Steering control sets the power level applied to the motors.
- 0 is move straight
- A postive number is more power for C than B
- A negative number is more powere for B than C
The Move Steering Block Duration control sets:
- Rotation – the number of complete rotations of the motor
- Useful for longer distances
- Degree – the number of degrees the motor rotates
- Useful for more precise movements
- Seconds – how long the motors will turn
- Useful for quick, approximate distances
- Note: Using time as a Durations control is risky, since changes in conditions or battery level will produce varying distances
The Move Steering Command Brake or Coast controll will either lock the wheels (Brake) upon completion of the command or allow the motors to drift to a stop (Coast)
- Note: The Brake setting causes an additional drain on the battery since it actively attempts to holds the motor output in place
Additonal Resources
Alternative Instructional Material
A useful Alternative Differentiated Instructional Material is STEMcentric's EV3 Introduction. You have to forward about 8 minutes to get to the section that covers the Move Steering from EV3 Trainer "Moving Straight" Step 3. Students should be able to complete the STEMcentric MOVE Exercise and end up with a solid command of each parameter in the Move Block (except the Steering control).
Additonally, the first half of the Alternative Differentiated Instructional Material STEMcentric's EV3 Action Blocks covers the operation of the Motor Blocks from EV3 Trainer "Moving Straight" Step 4.
Doing the Math
Students should use Proportional Math to calculate the Move block parameters required to achieve a prescribed straight movement, given the parameters from a prior known result. This Extended Differentiated Instructional Material descirbes the Scale Factor approach to teaching proportional Proportional Math for robot movement.
Have student be explicit about the Math they used to solve the “Sensabot” Challenge.
