           digitalWrite(rear_motor_b[i], LOW);
           analogWrite(front_motor_en[i], 0);
           analogWrite(rear_motor_en[i], 0);
+          motor_drive_target[i] = 0;
         break;
       }
     }

          digitalWrite(rear_motor_b[i], LOW);
          analogWrite(front_motor_en[i], TURN_SPEED);
          analogWrite(rear_motor_en[i], TURN_SPEED);
        break;

        case MOTOR_REVERSE_FULL:

          digitalWrite(rear_motor_b[i], LOW);
          analogWrite(front_motor_en[i], 0);
          analogWrite(rear_motor_en[i], 0);
          motor_drive_present[i] = 0;
        break;

        case MOTOR_FORWARD_FULL:
