As the flying speed of heavy aircraft is increasing and the flying attitude is becoming more and more complex, higher and higher technical requirements are put forward for the measurement accuracy of the aircraft's center of gravity. The hydraulic Weighing system provides a device for measuring and adjusting the aircraft's center of gravity through three-point support. A weighing module is installed at each support point, and the upper part of the weighing module is provided with a top. In the jacking process, the attitude of the aircraft can be obtained by gravity fitting to prevent accidents caused by excessive tilt Angle of the aircraft. When testing different models, the fitting parameters need to be reset, and the lifting heights of the three brackets need to be adjusted repeatedly. The operation time is long and the test efficiency is low. At the same time, the position of the plug needs to be adjusted repeatedly to align with the socket on the top of the aircraft, which can reduce but still not eliminate the side force. The weighing module and the top socket of the aircraft are not strictly point contact, but surface contact, and the application point is not accurate. Repeated adjustment requires high technical level of test personnel, the support point is not accurate, and there is a risk of rolover during the lifting process, resulting in damage to the wing contact with the ground. Most of the time in the test process is spent on the alignment of support points, but the accuracy, efficiency and versatility of the measured data cannot meet the development needs of aircraft gravity center measurement technology. The following aircraft weight and gravity center Measurement system applications:

Jack measurement

The jack method is very commonly used in measurement work, and the specific working principle is as follows: before the measurement work is carried out, the operator can park the aircraft on the flat ground to eliminate interference factors such as wind and magnetic field. After that, the top hole under the belly of the aircraft is regarded as the bearing point, between the top hole and the jack, the weighing module is used as the corresponding measuring component, and the load bearing of the weighing module is lifted by the jack, so as to better display the mediation function. In this process, the most commonly used method is three-point support measurement. In the specific operation process, one can place a jack in the front fuselage and another jack on the left and right wings. In addition, the actual weighing module load can realize the overall measurement of the aircraft weight, and by means of the torque balance principle, the longitudinal center of gravity position of the aircraft can be determined. In addition, in the process of carrying out the specific aircraft design work, the aircraft coordinate system should be mainly constructed, and the actual calculation and measurement results should be expressed in the coordinate system to ensure the comprehensive development of the measurement work.

Weighing platform measurement

This kind of measurement is mainly to place a weighing platform under the wheel of the aircraft, and add a weighing module to it, and in the actual three-point measurement process, three weighing platforms can be fully applied, at this time, the importance of the approach bridge traction will be shown. In order to strengthen the accuracy of the measurement, the relevant staff can use the drawing method or the analytical method according to the actual moment balance principle, and then present the body coordinates of the aircraft, which is also an important step in the gravity center measurement. From a theoretical point of view, the pressure of the wheel acting on the plane should be mainly vertical downward, and the weighing module located under the plane can realize its complete measurement. In order to eliminate the lateral force, relevant staff need to develop relevant measures according to the actual situation, such as releasing the brake during the reading process, measuring the weighing platform under the flat site, etc., so as to realize the full development of the entire measurement work.

Combined measurement of jack and weighing platform

In order to further improve the measurement accuracy of the actual weighing platform, a hybrid measurement form of jack and weighing platform is proposed. The specific measurement principle is as follows: a jack is placed on the actual weighing platform, and the whole weighing platform is used as the base of the jack to support the flight of the aircraft. In addition, through the jack operation, it can also implement the lifting operation of the aircraft, achieve the level adjustment of the aircraft, and with the help of the weighing platform, the perception can be predicted. In the actual measurement process, the weight of the jack should be subtracted according to the real-time measurement, which is also the most reasonable representation of the final weight of the aircraft.

Computational measurement at weight balance

At this stage, with the continuous development of the economy, the application proportion of large air passenger and cargo transport aircraft is increasing, especially for the gravity center measurement of large aircraft, its heavy balance system is a necessary condition of the system. From the perspective of practical development, many foreign companies such as Boeing and Airbus have used weighing balance and real-time calculation measurement programs. From the measurement of the ground weighing balance system, it can be seen that the weight of the entire aircraft fuselage is concentrated on the landing gear hydraulic buffer, if the aircraft tire, brake system and other weights are added together, the weight of the entire aircraft can be obtained. Generally speaking, the weighing module can be installed in the landing gear hydraulic buffer, which can measure the pressure under the buffer, and then better reflect the weight of the aircraft. In the process of measuring the ground load balancing system, the total aircraft weight is mainly supported by the hydraulic buffer of the lower landing gear, and then the weight of the aircraft tire and brake system is added to constitute the total aircraft weight. In the study of the aircraft center of gravity position, it is mainly presented by the sum of torque of the reference position, and then the specific total weight of the aircraft is calculated.