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Journal Article

Optimal Chassis Suspension Design for Towbarless Towing Vehicle for Aircraft Taxiing

2022-03-29
2022-01-0291
The towbarless aircraft taxiing system (TLATS) consists of the towbarless towing vehicle (TLTV) and the aircraft, of which the nose wheel is lifted and fixed by the picking up and holding system of the TLTV. The aircraft is towed to the destination in a long distance with a high speed of about 40 km/h only driven by the TLTV, which has the advantages of efficiency and economy by comparing with the traditional towing operation at a low speed of 5 km/h and with a short towing distance of about 50 m. However, the increase of the towing velocity leads to an deteriorate vibration problem in terms of the uncomfortable of the driver and reduction of the structure safe life limit, due to the lack of the chassis suspension for the vibration isolation of the TLTV. Therefore, the air suspension is introduced to the TLTV to alleviate the vibration. The dynamic model of the TLATS with air suspensions is derived.
Technical Paper

A Novel Position and Posture Measuring Method in the Docking of the Towbarless Towing Vehicle and the Aircraft

2023-04-11
2023-01-0129
Nowadays the ultrasonic radar, infrared detection, laser scanning radar or other perception technologies have been widely used in the automatic docking conditions. However, it’s not absolutely applicable in severe weather such as heavy rain and snow days, especially in the operation not allowed to fail, for example, the docking of the future unmanned towbarless towing vehicle (TLTV) with the expensive civil plane. A novel mechanism is proposed for relatively position and posture measuring between the TLTV and the aircraft nose tire during the automatic docking operation. The geometrical relationship between the towing vehicle and the nose tire is obtained by mathematical calculation. The position and posture of the nose tire have been obtained by splice angles and the length of rotatable rods connected with the vehicle during the docking operation.
Technical Paper

Collision Avoidance Study for Towbarless Aircraft Taxiing Systems on the Airport Apron Considering the Measuring Uncertainty

2023-04-11
2023-01-0782
The towbarless aircraft taxiing system (TLATS) consists of the towbarless towing vehicle (TLTV) and the aircraft. The tractor realizes the towing work by fixing the nose wheel. During the towing process, the tractor driver may cause the aircraft to collide with an obstacle because of the blind spot of vision leading to the accident. The special characteristics of aircraft do not allow us to modify the structure of the aircraft to achieve collision avoidance. In this paper, three degrees of freedom (DOE) kinematic model of the tractor system is established for each of the two cases of pushing and pulling the aircraft, and the relationship between the coordinates of each danger point and the relatively articulated angle of the TLATS and the velocity of the midpoint of the rear axle is derived.
Technical Paper

Improved Prandini Conflict Detection Algorithm Based on Trajectory Prediction

2023-12-31
2023-01-7100
As a traditional probabilistic mid-term conflict detection algorithm, the Prandini algorithm plays an essential role in ensuring flight safety in the aircraft route area. For the issue of mutation error in the calculation results of the Prandini algorithm, this research provides an improved Prandini conflict detection algorithm. First, the integral of the standard Gaussian distribution is solved using randomization. The minimum prediction interval moment is then calculated, and the critical time points at which conflicts may exist before and after that moment are approximated separately using a bisection method. N moment values are selected uniformly within the time range formed by the two critical time points. The instantaneous conflict probabilities for these N moments are calculated and the maximum value is selected from them as a measure of the likelihood of conflict between the two aircraft over the entire route for an extreme case.
Technical Paper

Overview and Research on Airworthiness and Safety of Electrical Propulsion and Battery Technologies in eVTOL

2023-12-31
2023-01-7116
This overview and study article scrutinizes the evolution and challenges of electric vertical takeoff and landing aircraft (eVTOL), with a primary focus on airworthiness and safety certification. The paper discusses key issues such as high-energy-density aviation-grade batteries and the light weighting of electrical propulsion systems. Utilizing scientific models and real-world data, the study outlines the required battery technology and electrical propulsion specifications for eVTOLs with effective commercial load capabilities. For eVTOLs operating in the 300 km range, aviation-grade batteries must achieve energy densities between 300-600 wh/kg. For those covering a 600 km range, the energy density requirements exceed 600 wh/kg. Compliance with stringent safety standards, including triple certification by the FAA under 14 CFR Part 23, is imperative. This article conducted research and offered flowchart of the complicated FAA standard, which is rare in existing articles.
Technical Paper

Study on Aircraft Wing Collision Avoidance through Vision-Based Trajectory Prediction

2024-04-09
2024-01-2310
When the aircraft towing operations are carried out in narrow areas such as the hangars or parking aprons, it has a high safety risk for aircraft that the wingtips may collide with the surrounding aircraft or the airport facility. A real-time trajectory prediction method for the towbarless aircraft taxiing system (TLATS) is proposed to evaluate the collision risk based on image recognition. The Yolov7 module is utilized to detect objects and extract the corresponding features. By obtaining information about the configuration of the airplane wing and obstacles in a narrow region, a Long Short-Term Memory (LSTM) encoder-decoder model is utilized to predict future motion trends. In addition, a video dataset containing the motions of various airplane wings in real traction scenarios is constructed for training and testing.
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