   unsigned long time_now = millis();
   unsigned long step_time = time_now - prev_update_time;
   prev_update_time = time_now;
-  ros::Time stamp_now = nh.now();
+  ros::Time stamp_now = ros_now();
 
   // odom
   updateOdometry((double)(step_time * 0.001));


  int32_t current_tick;

  sensor_state_msg.stamp = nh.now();
  sensor_state_msg.battery = checkVoltage();

  dxl_comm_result = motor_driver.readEncoder(sensor_state_msg.left_encoder, sensor_state_msg.right_encoder);

void loop()
{
  receiveRemoteControlData();
  uint32_t t = millis();
  update_time();
  if ((millis()-tTime[0]) >= (1000 / CONTROL_MOTOR_SPEED_PERIOD))
  {
    controlMotorSpeed();
