// Update is called once per frame
 void FixedUpdate()
 {
     for (int i = 0; i < person_num; i++)
     {
         if (WormsList[i] != null)
         {
             HeadController headController = WormsList[i].GetComponent <HeadController>();
             headController.Z_rotate_update(z_rotate_angle[i]);
         }
     }
 }