Evasive Maneuver to Space Shooter 2D.

Hey Guys, I am converting the Project Space Shooter to 2D, and I'm in trouble in the enemy's movement.

 using UnityEngine;
 using System.Collections;
 
 public class EvasiveManeuver : MonoBehaviour
 {
     public Boundary boundary;
     //public float tilt;
     public float dodge;
     public float smoothing;
     public Vector2 startWait;
     public Vector2 maneuverTime;
     public Vector2 maneuverWait;
 
     private float currentSpeed;
     private float targetManeuver;
 
     void Start ()
     {
         currentSpeed = GetComponent<Rigidbody>().velocity.y;
         StartCoroutine(Evade());
     }
     
     IEnumerator Evade ()
     {
         yield return new WaitForSeconds (Random.Range (startWait.x, startWait.y));
         while (true)
         {
             targetManeuver = Random.Range (1, dodge) * -Mathf.Sign (transform.position.x);
             yield return new WaitForSeconds (Random.Range (maneuverTime.x, maneuverTime.y));
             targetManeuver = 0;
             yield return new WaitForSeconds (Random.Range (maneuverWait.x, maneuverWait.y));
         }
     }
     
     void FixedUpdate ()
     {
         float newManeuver = Mathf.MoveTowards (GetComponent<Rigidbody>().velocity.y, targetManeuver, smoothing * Time.deltaTime);
         GetComponent<Rigidbody2D>().velocity = new Vector3 (newManeuver, 0.0f, currentSpeed);
         GetComponent<Rigidbody2D>().position = new Vector3
         (
             Mathf.Clamp(GetComponent<Rigidbody2D>().position.x, boundary.xMin, boundary.xMax), 
             0.0f, 
             Mathf.Clamp(GetComponent<Rigidbody2D>().position.y, boundary.yMin, boundary.yMax)
         );
         
         //GetComponent<Rigidbody2D>().rotation = Quaternion.Euler (0, 0, GetComponent<Rigidbody2D>().velocity.x * -tilt);
     }
 }