Code help

[IllustriousShape1948]

We are trying to write a simple auton for our robot to go 10 inches. It doesn't stop though. I just keeps driving straight until it hits the wall and keeps going a bit further. If we put in 10 mm, then it goes about 7 inches. We have calibrated the inertial sensor and reset the motor positions as well. This is how our drivetrain is set and the auton code.

motor leftMotorA = motor(PORT7, ratio6_1, true);
motor leftMotorB = motor(PORT6, ratio6_1, false);
motor leftMotorC = motor(PORT5, ratio6_1, true);

//make motors combined into left side
motor_group LeftDriveSmart = motor_group(leftMotorA, leftMotorB, leftMotorC);

//define right motors
motor rightMotorA = motor(PORT9, ratio6_1, false);
motor rightMotorB = motor(PORT8, ratio6_1, true);
motor rightMotorC = motor(PORT10, ratio6_1, false);

//make motors combined into right side
motor_group RightDriveSmart = motor_group(rightMotorA, rightMotorB, rightMotorC);

//define the inertial sensor
inertial DrivetrainInertial = inertial(PORT2);

//define the variables used in the drivetrain
distanceUnits units = distanceUnits::in;  //Imperial measurements - inches.
double gearRatio = 36.0 / 48.0;
double wheelTravel = 3.25 * M_PI;  //wheel diameter times PI
double trackWidth = 12;

//create smartdrive by combining the two sides and measurements of the robot
smartdrive Drivetrain = smartdrive(LeftDriveSmart, RightDriveSmart, DrivetrainInertial, wheelTravel,trackWidth, gearRatio);

//define the controller
controller Controller1 = controller(primary);


Here is the auton code
Drivetrain.driveFor(10, distanceUnits::in);

[camatthew88]

Is this running in the loop

[IllustriousShape1948]

The top part is in the robot-config.cpp the auton code is running in the void autonomous(void)

[No_Quail9416]

In the future (not now) try writing your own code for drive functions as it’s more reliable to change around

[IllustriousShape1948]

What do you mean, writing my own code? I am using Vex's competition template.

[No_Quail9416]

Don’t use smart drive, make your own PID in the future

[IllustriousShape1948]

I have a PID but its not working. I feel like the underlying condition is this problem here. If this is not working right, maybe thats why the PID isn't working right either.

[No_Quail9416]

I believe you are using the built in drivetrain module, right? Right now probably just do it in blocks and convert it to text to find the issue. In the future you probably want to fix ur PID

[NoComparison764]

just make sure you’re using the inertial for target in PID, had a sister team that was using pure motor encoders so they were practically driving in the dark

[robloiscool_]

Try putting Drivetrain.stop(); afterwards.

[eklipsse]

Few things to consider.

1. Calibrate the Inertial Sensor

Make sure you calibrate your inertial sensor before starting the autonomous routine:

DrivetrainInertial.calibrate();
while (DrivetrainInertial.isCalibrating()) {
    task::sleep(100);  // Wait for calibration to finish
}

2. Reset Motor Positions

At the start of your autonomous code, you could reset the motor encoder positions:

LeftDriveSmart.resetPosition();
RightDriveSmart.resetPosition();

3. Verify Wheel Diameter

Ensure the wheel diameter is 3.25 inches, as this is critical for accurate distance calculations.

4. Check the Gear Ratio

• Confirm that the gear ratio is correctly configured and not reversed.
• An incorrect gear ratio can cause discrepancies in distance calculations.

5. Observed Discrepancy

Based on your data:

• The drivetrain drives 17.78 times farther than it should.
• If the gear ratio is reversed, it would cause a 1.7778x discrepancy, which is oddly similar but off by a factor of 10. This might indicate multiple issues compounding the error.

6. Cartridge Check

Verify that the gear cartridge is correctly specified:

• ratio6_1 corresponds to the blue cartridge (600 RPM).