CANSparkMax vs Talons - Robot adaptability

[WesleyMcGinn]

Introduction

On Saturday, February 18th, our team had a plentiful dose of motor errors and major concerns for the CANSparkMaxs. Last year, we had several major Talon SRX issues at the Lakeview competition. In the midst of competition, if one motor type stops working, we may want to immediately change over to the other and diagnose the problem later. Because of this, I suggest that we incorporate functionality for CANSparkMaxs and Talons into our robot code.

Proposal

Similar to what is done in Weswerve.java, line 17, we could use a boolean statement at the beginning of each system class that reads true if we are using Talons and false if we are using CANSparkMaxs. Although this would add more code to the robot that may not be absolutely necessary, I think that it is worth the backup plan that it would provide us with.

Differences In Code Between CANSparkMaxs and Talons

	CANSparkMax Code	Talon SRX Code
Import 1	import com.revrobotics.CANSparkMax;	import com.ctre.phoenix.motorcontrol.can.TalonSRX;
Import 2	import com.revrobotics.CANSparkMaxLowLevel.MotorType;	import com.ctre.phoenix.motorcontrol.ControlMode;
Declaration	public CANSparkMax myMotor;	public TalonSRX myMotor;
Initialization	myMotor = new CANSparkMax(<CAN_ID>, MotorType.kBrushless);	myMotor = new TalonSRX(<CAN_ID>);
Set Speed	myMotor.set(<SPEED>);	myMotor.set(ControlMode.PercentOutput, <SPEED>);

Note: Replace <CAN_ID> with the CAN ID of the motor and replace <SPEED> with a value from -1 to 1.

[WesleyMcGinn]

Something else to keep in mind is the different references to encoder values from Talons and CANSparkMaxs:

	CANSparkMax Encoder Code	Talon SRX Code
Import	import com.revrobotics.RelativeEncoder;	No Encoder Import Needed
Initialization	myEncoder = myMotor.getEncoder();	No Encoder Initialization Needed
Set Value	myEncoder.setPosition(<ticks>);	myMotor.setSelectedSensorPosition(<ticks>);
Get Value	myEncoder.getPosition()	myMotor.getSelectedSensorPosition()

Additionally, NEOs and Talons spin in opposite directions. The following function may be needed, which works the same for both NEOs and Talons: myMotor.setInverted(true);

[WesleyMcGinn]

This issue was solved with the robot-motor-adaptability branch.

[WesleyMcGinn]

The new Motor.java class can be used as follows:

Action:	Code for Action:
Import	import frc.robot.systems.Motor;
Declaration	public Motor myMotor;
Initialization	myMotor = new Motor(<CAN_ID>, <IS_TALON?>, <DIRECTION>);
Set Speed	myMotor.set(<SPEED>);
Get Encoder Value	myMotor.getEnc()
Set Encoder Value	myMotor.setEnc(<ENCODER_TICKS>);
Set Motor Position	myMotor.goTo(<ENCODER_TICKS_FROM_START>);
Update*	myMotor.update();

*This function must be called periodically if you used the .goTo function. It will update the speed of the motor based on how far it is from the desired encoder value.

[WesleyMcGinn]

ERROR!

The motor function myMotor.goTo(<ENCODER_TICKS_FROM_START>); was just found to have an issue: The motor will adjust to go to its original location, but will not go to any other position.

This will be worked on immediately.

[WesleyMcGinn]

Fixed Issue

This issue was resolved by the last commit. The motors should now automatically adjust to reach their set positions when the update() function is called.