   if (buttons & (1<<0))  
   {
     move[LINEAR] = true;
-    saved_tick[RIGHT] = sensor_state_msg.right_encoder;
+    saved_tick[RIGHT] = current_tick[RIGHT];
 
     diff_encoder = TEST_DISTANCE / (0.207 / 4096); // (Circumference of Wheel) / (The number of tick per revolution)
   }
   else if (buttons & (1<<1))
   {
     move[ANGULAR] = true;
-    saved_tick[RIGHT] = sensor_state_msg.right_encoder;
+    saved_tick[RIGHT] = current_tick[RIGHT];
 
     diff_encoder = (TEST_RADIAN * TURNING_RADIUS) / (0.207 / 4096);
   }

{
  DEBUG_SERIAL.println("---------------------------------------");
  DEBUG_SERIAL.println("EXTERNAL SENSORS");
  DEBUG_SERIAL.println("---------------------------------------\n");
  DEBUG_SERIAL.println("bumper : ");
  DEBUG_SERIAL.println("cliff : ");
  DEBUG_SERIAL.println("sonar : ");
  DEBUG_SERIAL.println("illumination : ");
  DEBUG_SERIAL.println("led : ");

  DEBUG_SERIAL.println("---------------------------------------");
  DEBUG_SERIAL.println("OpenCR SENSORS");
  DEBUG_SERIAL.println("---------------------------------------\n");
  DEBUG_SERIAL.println("battery : ");
  DEBUG_SERIAL.println("button : ");
  DEBUG_SERIAL.println("imu : ");
  
  DEBUG_SERIAL.println("---------------------------------------");
  DEBUG_SERIAL.println("DYNAMIXELS");
  DEBUG_SERIAL.println("---------------------------------------\n");
  DEBUG_SERIAL.println("torque : ");
  DEBUG_SERIAL.println("left_encoder : ");
  DEBUG_SERIAL.println("right_encoder : ");

  DEBUG_SERIAL.println("---------------------------------------");
  DEBUG_SERIAL.println("TurtleBot3");
  DEBUG_SERIAL.println("---------------------------------------\n");
  DEBUG_SERIAL.println("odometry : ");    

  // Serial.println("   id : " + String(scanned_id[i]) + "   Model Name : " + String(dxl_wb.getModelName(scanned_id[i])));
}

  delta_theta = theta - last_theta;

  // compute odometric pose
  odom_pose[0] += delta_s * cos(odom_pose[2] + (delta_theta / 2.0));
  odom_pose[1] += delta_s * sin(odom_pose[2] + (delta_theta / 2.0));
  odom_pose[2] += delta_theta;

  // compute odometric instantaneouse velocity

  v = delta_s / step_time;
  w = delta_theta / step_time;

  odom_vel[0] = v;
  odom_vel[1] = 0.0;
  odom_vel[2] = w;

  last_velocity[LEFT]  = wheel_l / step_time;
  last_velocity[RIGHT] = wheel_r / step_time;
  last_theta = theta;

  return true;
