In the zone: autonomous strategy

How do you guys program so that robot can pull/push/lift and drop/move to 5 point zone in the autonomous?

We find it challenging to go to mobile goal and pick up consistently. In the competition I observed that volunteers often place mobile goal on the blue/red tile at slightly different position before start of every game.

If the position of the mobile goal is not precise what are the strategies to reach and pull/push/lift the mobile goal through programming? Our robot can’t even go in straight line consistently - if it touches a yellow cone on the way to mobile goal the it steers off as well. Is it mandatory that we use line tracker or something else/more?


Use PID.

Indeed, it is plausible to move a mobile goal to the 5-10-20 during auton. Many teams even do a 22 point auton involving a preload + mobile goal in the 20. Like M8R said, a PID control will greatly assist you in this task. However, factors that contribute are the starting position of the robot, accuracy of field setup, and you’re drive’s torque.

If you are having trouble, I’d advise offsettting the start position of your robot to the side away from the wall. Robots can usually push cones that are free standing but get pushed away by cones resting on the wall.

There is a tolerance as to how accurately field objects need to be placed but most often you can politely ask a referee to center a mobile goal in the tile.

Thanks all! Now I understand bit more. So, by watching few videos I understand that for this PID controller function the input is value from sensor(s). Which and how many sensors (hardware) are typically used for arm and robot body? 1 Potentiometer for arm and for each wheel a shaft encoder and maybe ultrasonic range finder? I am guessing potentiometer to accurately position the arm, shaft encoder to keep robot moving in a straight line, and ultrasonic range finder to deter how close the robot is from a mobile goal? Or am I missing something?

Using shaft encoders will also tell you how far you’ve driven, no need for ultrasonic…

Okay. So I can use shaft encoders on arm and all of the wheels. Is that correct? No need for gyroscope or potentiometer or ultrasonic range finder?

a gyro will help with how far your turning, and make it easier to program, but yes you can do it that way

I agree