Java - Gradual Acceleration in Autonomous Help

Technical Java
1

Hello. Thanks to all for the help in the past. We are looking to more gradually accelerate the bot in autonomous rather than just immediately ramping to 80 or 90% speed.

Would someone be willing to look at my code (java) and give me some suggestions or point me in the right direction to allow for a more gradual acceleration in autonomous.

Here is a link to the code: GitHub - EricTheOtterBot/OtterBots-2023-code

The autonomous I’ve been working on is called balanceAuto, which uses a command called AutoBalance. Within AutoBalance, I set the speed to -0.8. Looking for a way to gradually speed up that number.

Thanks so much.

2

Adjusting the ramp rate of the motors will increase the time needed to reach top speed, thus producing more gradual acceleration.

1 Like
3

You could possibly try turning down the current limit on your drive motors for autonomous and then reset them for teleOp. It might be a little janky but it’s working well for our lift so far.

4

Where is this done in the code?

5

If you are using a SwerveControllerCommand, you are passing in a trajectory that has a config in which you specify the path’s velocity and acceleration. Have you tried lowering these values?

6

I have. The problem with this is that I can’t/don’t know how to use the code I put into my AutoBalance command. In that command I specify that it should go forward until the gyro’s pitch is less than -12 degrees. If there is a way I could put that gyro code into the SwerveControllerCommand, that would definitely be optimum.

7

Acceleration limiting is often down with Slewrate Limiters. By setting the power equal to filter.calculate(input);you could gradually let the value increase from 0 to 90%

You also could choose to not run at 90% power and instead do 50%. A lot of people find that if you don’t need the time savings, this is a lot more consistent way to do an auto.

Please please ask me if you want any clarification on the above. Happy to help!

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8

Typically wherever you construct your drivetrain.

public DriveSystem() {
fieldOriented = true;

// Capitalized and underscored variable names are statically imported constants from Constants.java
frontLeft = new CANSparkMax(FRONT_LEFT_MOTOR, MotorType.kBrushless);
backLeft = new CANSparkMax(BACK_LEFT_MOTOR, MotorType.kBrushless);
frontRight = new CANSparkMax(FRONT_RIGHT_MOTOR, MotorType.kBrushless);
backRight = new CANSparkMax(BACK_RIGHT_MOTOR, MotorType.kBrushless);

if (Robot.checkType() == Robot.RobotType.A_BOT) {
  frontLeft.setInverted(false);
  backLeft.setInverted(false);
  frontRight.setInverted(true);
  backRight.setInverted(true);
} else {
  frontLeft.setInverted(false);
  backLeft.setInverted(false);
  frontRight.setInverted(true);
  backRight.setInverted(true);
}

// Current limits on breakers are set to 40 Amps
frontLeft.setSmartCurrentLimit(CURRENT_LIMIT);
backLeft.setSmartCurrentLimit(CURRENT_LIMIT);
frontRight.setSmartCurrentLimit(CURRENT_LIMIT);
backRight.setSmartCurrentLimit(CURRENT_LIMIT);

// Voltage compensation in volts
frontLeft.enableVoltageCompensation(NOMINAL_VOLTAGE);
backLeft.enableVoltageCompensation(NOMINAL_VOLTAGE);
frontRight.enableVoltageCompensation(NOMINAL_VOLTAGE);
backRight.enableVoltageCompensation(NOMINAL_VOLTAGE);

// Time in seconds to reach max velocity in open loop
frontLeft.setOpenLoopRampRate(RAMP_RATE);
backLeft.setOpenLoopRampRate(RAMP_RATE);
frontRight.setOpenLoopRampRate(RAMP_RATE);
backRight.setOpenLoopRampRate(RAMP_RATE);

This is our drivetrain constructor from 2022.

9

So what I ended up doing is making a ton of commands to simply set it to 10% more, then return it as true and move to the next command, which is 10% more than the last one. Sort of a pathetic fix because I didn’t set an acceleration, but it works anyway. Thanks for all of your help and advice! I appreciate your insight. Hopefully, I’ll get my github updated to the current code.

P.S: Does anyone know if the link at the top of this post will update to show the latest code, even if I don’t change the link itself? I don’t want people to click on that link and see old code.

Thanks again.

10

I guess I can answer myself. The link still works.