## 2 Working Principle  
Among the various helicopter landing assistance systems currently in service, the most widely used is the 'Aircraft Ship Integrated Secure and Traverse System (ASIST)' proposed by Canada, which has the advantages of high automation, short landing assistance time, and high adaptability to sea conditions [4; 5; 49]. As shown in Figure 1, the ASIST system consists mainly of landing indicator lights, laser sources, probe rod, track, correction device, camera, control console, and hydraulic traction system. As shown in Figure 2, the process of a marine helicopter landing on a ship with the aid of ASIST can be segmented into the following stages: helicopter approaches the ship, helicopter hovers above the deck, helicopter lands on the deck, and finally, ASIST guides the helicopter to its predetermined location. Upon approaching a vessel, the marine helicopter is initially identified and tracked by a camera installed on the deck. This camera retrieves the target laser source information of the helicopter, calculates the helicopter's location in real time, and transmits it to the control console. The control console provides illuminated guidance information to the pilot via light indicators, routes the helicopter under the guidance of landing indicator lights, and navigates it to the designated landing area. Simultaneously, the control console apparatus controls the hydraulic traction system to drive the correction device to track the helicopter's position but always maintains a suitable safety distance from the helicopter. When the helicopter is positioned appropriately and the external environment permits, the helicopter initiates its descent; the instant the helicopter lands on the deck, the hydraulic traction system drives the correction device to capture the probe rod on the belly of the helicopter and secures the helicopter in the landing area. Upon completion of the capture and tethering process, the operator controls the hydraulic traction system to maneuver the helicopter along the track to the hangar. Figure 1: Schematic diagram of ASIST. The hydraulic traction system, which is the main power equipment of the system, is mainly used to track and tow correction devices and helicopters. However, this system has shortcomings, such as slow response speed and poor steady-state characteristics during operation. It is also affected by complex pipelines in the hydraulic system and oil leakage under high loads, resulting in high-energy consumption of the hydraulic traction system. In response to the problems existing in the hydraulic traction system, this article designs a new type of electric-driven helicopter traction system, whose composition and transmission scheme are shown in Figure 3.  
The working principle of this system is as follows: the control system directly controls the output speed of the motor and drives the steel cable drum to rotate through a reducer. The steel cable wrapped on the steel cable drum moves along the deck track and pulls the helicopter through the pulley block traction correction device. The red circle in the figure represents the probe rod mentioned earlier. At the same time, the steel cable drum drives the cable drum to rotate through chain transmission, allowing the cable to follow the movement of the correction device. Because of the complex and unpredictable marine environment that affects the recovery of helicopters on ships, especially the rapid and significant shaking of the ship deck, the system load has the characteristics of high frequency and high amplitude. Using a controller with static PID parameters can greatly reduce control accuracy and amplify noise in the differential process. This study combines fuzzy PI control and permanent magnet  
Figure 3: Transmission scheme of the electric drive traction system. Figure 2: Schematic diagram of helicopter recycling process.