How to fix the code so that the object is only directed in a straight line, without "drifting"?

Question

C++ / C#

Hello, here is the code:

spoiler

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class RotateTank2 : MonoBehaviour
{


    public Transform Selftransform;

    private Vector3 _force;


    private int rotate = 1;






    // Use this for initialization
    void Start()
    {

    }

    // Update is called once per frame
    void FixedUpdate()
    {

        Selftransform.position += _force;

        if (rotate == 1)
        {
            transform.Rotate(0, 0, 2);

        }

        if (Input.GetKey(KeyCode.D))
        {
            rotate = 0;
            _force += (Selftransform.up * Time.deltaTime) * 0.1f;


        }
        else
        {
            _force = Vector3.Lerp(_force, Vector3.zero, 10);
            rotate = 1;
        }

    }
}

By pressing the button, the tank moves in a straight line, but when it collides with another object, it moves along the vector in the same way in a straight line, but sideways. How to do so. so that the object moves only in a straight line, regardless of the influence of another force on it (that is, how to repeat the forward movement of a real tank).

Answer 1

1. Turn off collision physics and move through transform
2. or use a perfectly elastic material and turn off roll and roll inertia.

Answer 2

There is a "look at" function - lookAt(target.tranform.position); change the rotation so that the blue arrow points forward of the tank and apply this function, it should work.