Unity машина

using UnityEngine;
using System.Collections;
using System;
 
public class MoveTank : MonoBehaviour {
    public Rigidbody rb;
    public Vector3 eulerAngleVelocity;
    public Vector3 targetPosition;
    public bool isGrounded = false;
    public int vector;
    // Use this for initialization
    void Start () {
        rb = GetComponent<Rigidbody>();
    }
    
    // Update is called once per frame
    void FixedUpdate () {
 
        if(isGrounded)
        {
            vector = Convert.ToInt32(-Input.GetAxis("Vertical") * 400);
        }
        rb.AddForce(transform.rotation * Vector3.forward * vector);
        int rotate = Convert.ToInt32(Input.GetAxis("Horizontal") * 4);
        Quaternion deltaRotation = Quaternion.Euler(new Vector3(0, rotate * 40, 0) * Time.deltaTime);
                rb.MoveRotation(rb.rotation * deltaRotation);
    }
 
    void Update()
    {
        Vector3 fwd = transform.TransformDirection(Vector3.down);
        RaycastHit hit;
        if (Physics.Raycast (transform.position, -Vector3.down, out hit)) {
            Debug.DrawLine (transform.position, hit.point, Color.cyan);
            isGrounded = true;
        } 
        else 
        {
            isGrounded = false;
        }
    }
}