Instruction Guide: Moving Straight
Have students work through the self-paced lesson "Moving Straight" video from the "Behaviors" page in "NXT Video Trainer 2.0" .
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).
The key points are:
The Move command Port setting choose which ports on the NXT Brick will be controlled by this block
-
Note: When two ports are selected, the Move 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 NXT-G
The Move Command Power sets the power level applied to the motors
- 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.
The Move command Duration can be controlled by:
-
Rotation – the number of complete rotations of the output
- Useful for longer distances
-
Degree – the number of degrees the output 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
-
Unlimited – motors will stay on until instructed to do otherwise by the program
- Note: all motors shut down at the end of a program, so an unlimited Duration Move block at the end of a program will only turn the motors on for a brief time
The Move command Next Action will either lock the wheels (Brake) upon completion of the command or allow them 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
The Move command Direction sets the direction of rotation
- Note: The"Stop" Direction setting will stop the motors, but the Next Action setting will determine whether the motors are locked or left floating
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.
Have student be explicit about the Math they used to solve the “Close Shave” Challenge.
