Innovative Automation of Landing Gear Using Programmable Logic Controllers

This article explores the widespread application and importance of the Programmable Logic Controller (PLC) in industry. PLC, as an industrial controller designed specifically for industrial environments, occupies an important position in the field of industrial automation control due to its advantages of being less susceptible to interference, high reliability, easy programming, fast installation, and small size. With the rapid development of PLC technology, great progress has been made in the development of technology, hardware, and software, resulting in increasingly powerful functionalities and significantly enhanced system development and compatibility. This paper mainly analyzes the design ideas and applications of PLC in life and industry in detail, aiming to research PLC and find more scenes in industry fields in which PLC can participate. PLC has a wide range of applications and significant importance in industry. The continuous progress and innovation of its technology will bring more opportunities and challenges to the field of industrial automation control. In the future, with the deepening development of advanced manufacturing models such as Industry 4.0 and intelligent manufacturing, PLC technology is expected to play a greater role in more fields and promote industrial automation to a higher level.

This study presents the development of dead-time compensator with Proportional Integral-Derivative (PID) controller and their implementation in real-time using the Programmable Logic Controller (PLC) on a heater-furnace system that constitute the temperature process. Though PID controller is effective to most of the processes, it has draw backs when used to control the processes with significant dead time. Therefore to eliminate the effects of long dead time, the dead-time compensator combined with PID is proposed. The control equation for the proposed dead time compensator is developed using the mathematical model of heater-furnace system and ladder logic program is created in GE Fanuc Versamax PLC. The PID controller is tuned using process reaction curve method and programmed in PLC. The proposed controller has an outer loop control mechanism with dead time compensator which feeds the inner loop PID controller. The effects of dead time on the performance of PID controller are eliminated through the outer loop control mechanism whose output does not contain modelling errors. The results of the proposed dead-time compensator with PID are compared with the results of the conventional PID controller without dead time compensation for both steady state response and servo-regulatory response. The results of the proposed controller show better improvement in the time domain specifications compared to conventional PID controller.

The use of the programmable logic controller has advanced tremendously since its introduction in the late 1960’s. The programmable logic controller, affectionately known as the PLC in today’s industries, was first introduced as an electrical control relay replacer. The purpose of this paper is to assist those who are considering the application of a PLC in their facility to better understand where programmable logic controller technology has advanced to today. Paper published with permission.

The purpose of this paper is to present a programmable logic controller (PLC) control system that is applied to the main feedwater process of a pressurized water reactor, construct a structure that the alternative system is a hot backup to the operating system between PLC and the original analog instrument control system, overcome the draw backs of TI545 type PLC control module, and implement an advanced digital control algorithm to improve the control performance simultaneously. Successful results are obtained from this scheme. Implementation indicates that the PLC control system improves the performance of both steam generator water levels regulation and disturbance rejection.

The Proportional-Integral-Derivative (PID) controller, already known for its stability, is widely used in industrial applications and integrated into many Programmable Logic Controllers (PLCs). However, most PLCs do not support the self-tuning mechanism for PID controller parameters. Therefore, users must manually adjust several times to achieve the desired outcomes. This manual adjustment is time-consuming and must be repeated as control object parameters change over time. This study proposed a fine-tuning mechanism for the PID controller’s parameters based on a fuzzy-PD controller. The mechanism was designed and simulated using MATLAB/Simulink on an identified plant, then converted into a Structured Control Language (SCL) code for implementation on the PLC programs.Experimental results on the Siemens S7-1200 PLC demonstrated the proposed mechanism’s effectiveness in stabilizing the thermal plant by adjusting the initial parameters of the integrated PID controller. The system response was more stable, and the overshoot was minimized in comparison with the built-in auto-tuning feature on the S7-1200. Specifically, overshoot decreased to 0.79% from 0.94%, and the setting error declined to 0.1 °C from 0.45 °C. The above results indicate the effectiveness of the proposed self-tuning mechanism when used to improve the quality of PID controllers in PLCs. In addition, due to its ability to self-tuning parameters, it helps users reduce the time required to design PID controllers.

One of the major tasks in the design and optimization process of a new landing gear system for an unmanned aerial vehicle (UAV) is to accurately determine the loads during the landing event, especially if the landing gear is considered unconventional. The work being presented describes a new approach to simulate landing events for some of the UAV's unconventional landing gears produced by General Atomics Aeronautical Systems, Inc. (GA-ASI), such as Predator A and Predator B series. GA-ASI selected ABAQUS/Explicit®, which is part of the ABAQUS suite of finite element analysis software, for its nonlinear, transient dynamics capabilities. The tricycle landing gear systems in Predator A and Predator B consist of a very stiff nose strut equipped with a shock absorber and highly flexible main gear struts made out of composite materials designed to absorb the landing event with elastic strain energy and frictional energy dissipation with tire scrubbing. The peak loads during the landing event are highly dependent on the complicated ground interactions with the tires during the initial contact and spin-up event. Geometric nonlinearity effects due to large displacements in the composite struts are accounted for in ABAQUS/Explicit®. The tires are modeled in detail with internal pressure simulated by hydrostatic fluid elements and the rubber material represented by hyperelastic elements embedded with rebar elements to model the tire reinforcements. A slip-rate based friction model governs the contact behavior between the tires and the ground. Landing gear struts are modeled using beam elements with stiffness validated by empirical load-deflection data. Shock absorbers' elastic and damping characteristics are defined by connector element behaviors. Bearing friction at the nose landing gear shock absorbers' piston-cylinder interface is also considered. Simulation results show a time history of landing loads at the wheel axles and deflection for the landing gear struts during the entire landing event. The results are then compared to and validated by extensive test data.

A unique, beneficial feature of rotorcraft is their flexibility in aircraft-to-ground interfacing. For a variety of reasons, hard landings can occur when the descent rate of the aircraft is larger than intended. The resulting impact can result in vehicle damage, structural failure, injuries, etc. To reduce these risks, an attractive solution is the implementation of a robotic legged landing gear (RLLG) system. The system softens a hard landing by acting as a shock absorber with a relatively large stroke, allowing the aircraft to decelerate over a much larger distance compared with a tradition landing gear system. This paper explores the mitigation of rotorcraft hard landings via RLLG through a comprehensive multibody dynamics simulation tool. The purpose of this study is to demonstrate the efficacy of the RLLG as a robust solution to reduce loads during hard landings for multiple landing configurations. The results show that when using RLLG in place of conventional landing gear, peak loads are reduced by approximately 70–90%, depending on the landing conditions. Through Monte Carlo simulation, robotic landing gear system performance is shown to be robust to uncertain conditions.

In this chapter, first, basic information about the landing gear (definition, purpose, and duties, etc.) is given. Examples of different aircraft are given throughout the chapter. Systems in large aircraft such as extend-retract mechanisms are explained on Boeing 737 aircraft. As mentioned in the chapter introduction, landing gears are the elements that provide contact with the ground during the landing—takeoff phases and movements on the ground (during taxi), the friction resistance is minimized, and they best absorb the loads caused by the horizontal and vertical movements of the aircraft. Afterward, different landing gear layouts and their usage areas, advantages, and disadvantages are mentioned. Landing gear struts, which are one of the basic elements of the landing gear and provide structural strength, are mentioned. By specifying the characteristics of different strut structures, the damping structure of the energies arising from the landing is explained. After the strut structures, wheels, tires, and brake structures, which are the other basic elements of the landing gear, are explained. Since there are retractable landing gears in large aircraft, the extend-retract mechanisms of the main and nose landing gear, their controls, and indicators are mentioned. Finally, the nose wheel steering mechanism that provides guidance during movement on the ground and the tail skid structure that prevents the tail from hitting the ground directly during takeoff are mentioned.KeywordsLanding gearMain landing gearNose landing gearExtend-retract mechanismAeronautics

This study investigates the substantial challenges that landing gear systems face due to increased aircraft speeds and traffic volumes, focusing particularly on bird strike incidents. By utilizing the Smoothed Particle Hydrodynamics (SPH) method alongside a rigid-flexible coupling finite element model, we analyzed the dynamic characteristics of bird impacts on ten typical landing gear structures. The simulations indicated that stress peaks exceeding 1200 MPa occurred in the nose landing gear pipelines, drag brace, spring, and main landing gear pipelines post-impact, leading to severe damage and loss of functionality. The aluminum drag brace displayed deformations greater than 15 mm, which poses significant safety risks. Additionally, a positive correlation was observed between peak structural deformation and bird impact speed on the main landing gear’s upper locking rod, with larger deformations inducing significant concentrated stress in the pin joints, which escalates with increased speed. Structures not directly impacted by the bird strike maintained sufficient rigidity, though certain critical areas require enhanced strength and protective measures such as reinforced panels in the design. This research provides theoretical support for designing bird strike protection in landing gear systems.

Aircraft interacts with the ground through landing gear system, while taxiing down the runway.Under rain or snow conditions, water film splashed by aircraft tires during taxiing on water-covered runways adheres to the landing gear, leading to ice accretion under low-temperature conditions, which may directly compromise aircraft takeoff and landing safety. Due to the substantial resource consumption required for experimental investigation of this problem, numerical simulation was employed to model the phenomenon.The water film icing process can be divided into two main stages: the formation of water film on the landing gear caused by tire spray, and the subsequent icing and heat transfer process of the splashed water film on the landing gear, this study conservatively simplifies the tire spray phenomenon as a typical liquid-solid two-phase coupling problem. A Finite Volume Model simulating water accumulation dynamics on landing gear tires was developed in Fluent software, based on extreme runway water accumulation conditions and extreme navigation weather scenarios during takeoff of a domestic civil aircraft model. The model incorporates coupled tire-water film-landing gear interactions. The VOF (Volume of Fluid) model and mesh motion are employed to calculate the water film thickness on the landing gear. A conservative thermodynamic equilibrium equation is then constructed based on boundary conditions to estimate the ice accretion thickness. The article analyzed the influence of external factors (aerodynamic drag, gravitational force, etc.) on water film thickness. The calculation results indicate that a conservative estimation of ice accretion derived from water film thickness does not compromise takeoff and landing safety, thereby validating that under rainy or snowy weather conditions with water accumulation on the runway, the conservative maximum icing thickness resulting from wheel spray water and landing gear water accumulation during aircraft taxiing will not exceed a level sufficient to pose a threat to aircraft takeoff and landing safety.

The model of aircraft landing gear hydraulic system is build by software of AMESim. Under the AMESim environment, a hydraulic simulation of the nose landing gear of aircraft is constructed. The simulation model of the component is built by graphical modeling method. Setting two case faults parameters of landing gear actuating cylinder leakage and air into oil, it obtains faults symptom of hydraulic system. The Internal characteristics, Interrelation and motion Law is shown for landing gear system various components. Combining hydraulic system simulation with fault diagnosis effectively, it can provide reference for fault analysis and design improvement of landing gear hydraulic system.

Electrical linear actuators reduce the weight of landing gear retraction / extension mechanism which helps in keeping the gross takeoff weight of aircraft weight low. Reduction in weight of the aircraft has manifold advantages in which noticeable are increased endurance, range, climb performance, acceleration performance and fuel efficiency. Use an electrical linear actuator in landing gear system is a simplification in the kinematics of landing gear retraction / extension sequence. In this research, a retraction / extension mechanism for nose landing gear (NLG) of a MALE UAV has been designed and tested according to FAR CFR 25.729. The design process of a Retractable Landing Gear System Mechanism (RLGS) started with selection of pivot point on NLG and axis for the rotation in free space available which resulted in least power requirement. Pivot point was selected such that no part of gear posed hindrance to other part of an aircraft. Next, the path of rotation about pivoting axis and position kinematics were calculated using vector loop closure equation. Essential parameters regarding retraction / extension sequence were calculated from trigonometry. Forces and power required for complete retraction / extraction sequence were calculated. During the research, it was found that retraction force on NLG depended upon the aerodynamic drag, inertial loads and gravitational force. In this research analysis of these forces is presented with much detail. Effect of velocity variation of linear actuator on the retraction force is commented upon. Computational analysis is carried out using multibody dynamics MSC ADAMS® software. The research concluded with experimental validation of a planner triangular retraction mechanism of NLG actuated by electrical linear actuator.

Drying food products using traditional methods relying on sunlight takes a relatively long time, especially with unpredictable weather conditions. Essentially, artificial drying using heat-based equipment provides several advantages, including: independence from weather conditions, adjustable drying capacity, controlled temperature, no need for extensive space, controlled drying conditions, and guaranteed and uniform drying quality. Therefore, this design aims to create a food drying apparatus with PLC control. PLC is used as the controller for this drying apparatus, allowing automatic drying of certain types of food. In this design, we connect a DC motor to rotate the drying cylinder with a PLC device by creating a ladder diagram and determining the inputs and outputs in the CX-Programmer application. The design utilizes three inputs and two outputs. It is important that the I/O is readable by the PLC so that the system operates according to the programmed instructions.

A stability test chamber simulates specific environmental conditions and tests a product or material in the manufacturing stage. The tested product or material is then analyzed about its shelf-life estimation related to the state and durability of the product for a certain period. The main parameter that must control accurately is temperature. Programmable Logic Controller (PLC) as an industrial computer control system has been widely used. In this paper, the temperature control system was designed based on PLC and supervisory control and data acquisition (SCADA). The PLC and SCADA would indirectly control the heater. The PLC was feeded from the temperature sensor for real-time temperature inside the test chamber. Received temperature value, compared to the temperature set point. The validation and verification of controlled temperature inside the chamber were also investigated. The system was designed on a miniaturized chamber using commercial PLC and SCADA, Stepper motor, slide regulator, heater, and the temperature sensor PT100. The temperature test point for validation and verification was performed at 35 °C, 45 °C, and 55 °C. The result showed that The PT100 successfully had an excellent response to the temperature test point. The correction value for temperature is as high as 0.6 °C with a deviation of 1 %.

- Airplane is a very important mode of transportation, one of which is ATR aircraft. In this study, the type of aircraft used was the ATR 72-600 aircraft. One of the safety factors that need to be considered on aircraft is the landing gear system. The landing gear system regulates the wheel system on the aircraft for landing and also taking off. Given the importance of ensuring that the plane's wheels are securely locked or not, an up lock box system is needed on the landing gear. In the Up Lock Box system, it is not directly visible from the outside so that the working mechanism is not widely known. This study aims to determine the workings of the up lock box nose teaching aid system on the landing gear and to make a trial up lock box nose teaching aid on the landing gear. The research method begins with a literature study, then looks for design references, namely from the ATA 32 training manual. After that, make a design using the image of the up lock box from the ATR 72 aircraft, assemble the demonstran tool, calibrate and test the demonstran tool. The conclusions in this study are, how the up lock box teaching aids work in accordance with the up lock box working concept in the training manual, the results of the design and manufacture of props accompanied by modifications, as well as the test results on up lock box props in accordance with the up lock work concept box. The size of the props that have been made has a length of 37.8 cm and a width of 16.2 cm.