Autonomous inconsistent turn and movement

VEX IQ General Discussion
1

We are using RobotC for Vex IQ autonomous. The turns and movements are always inconsistent, works perfect for first 2-3 times then after some time it will miss the hubs while turning.

We are using sensor to check the angle turn and 4 omni wheels . Any suggestions?

Thanks in advance.

2

If you are using a gyro, I would suggest the following:

Turn once to the angle you want the robot to turn to minus 30, then proceed to turn the turn/motor speed down to about 15% and turn the remaining degrees. You can then turn motor speed back to 100% and continue with your program.

Otherwise, if you do the turn all in one go there will be some drift from the omni wheels and the robot may overturn, presenting you with inaccurate results each time.

3

Could you post some code and also a picture of your robot? That will help us to make suggestions.

@Seb suggestion is a really good one.

4

Thanks for your help @Seb

5

resetGyro(Gyro);
wait(1,seconds);
setMotor(frontLeftMotor, 100);
setMotor(frontRightMotor, -100);
waitUntil (getGyroDegrees(Gyro) <= -28);
setMultipleMotors(80, frontLeftMotor, frontRightMotor, noMotor, noMotor);
stopMultipleMotors(frontLeftMotor, frontRightMotor, noMotor, noMotor);
setMotorTarget(armRightMotor, -828, 100);
wait(2, seconds);
forward(1.35, rotations, 100);
moveMotor(armRightMotor, 0.5, seconds, -90);
backward(0.8, rotations, 50);

  moveMotor(armRightMotor, 0.8, seconds, 90);
resetGyro(Gyro);
setMotor(frontLeftMotor, -100);
setMotor(frontRightMotor, 100);
waitUntil (getGyroDegrees(Gyro) >= 20);
setMultipleMotors(80, frontLeftMotor, frontRightMotor, noMotor, noMotor);
stopMultipleMotors(frontLeftMotor, frontRightMotor, noMotor, noMotor);
wait(0.1, seconds);
forward(3, rotations, 100);
wait(2, milliseconds);
6

@Raj73 Had that problem, now we are only using 2 omni wheels and the gyro is consistent. I think there is a little drift with using 4 omni wheels. Also a slower drive speed helps with consistency. They are also using the encoders for rotation count instead of a time delay, which dramatically helps with accuracy. The kids have a 38 driver skill and autonomous combined now with their changes.