Hello. I have a mobile robot and I want to move it to a certain position using cubic polynomials. Let's say that the initial position of the robot is ( 0,0 ) and the goal position is ( 10 , 5 ). I wrote a code using cubic polynomials and my problem is that the robot doesn't move to the goal position exactly. I tested it a lot of times. I know that gazebo has deviations. For example, if the goal position is (10,5) ,the robot moves to ( 10.7 , 3.4 ) If the goal is (5 , 5) ,the robot moves to ( 5.7 , 3.2 ) If the goal is ( -5 , 5 ) ,the robot moves to ( -0.3 , 3.7 ) .Here you can see a big deviation. I don't know why... Firstly, I want to know if something's wrong with my code. Secondly, I want to know how to move the robot to the goal position with bigger accuracy.

See my code using cubic polynomials here

Thanks in advance.