Optimal control based coordinated taxiing path planning and tracking for multiple carrier aircraft on flight deck

Coordinated taxiing planning for multiple aircraft on flight deck is of vital importance which can dramatically improve the dispatching efficiency.In this paper,first,the coordinated taxiing path planning problem is transformed into a centralized optimal control problem where collision-free conditions and mechanical limits are considered.Since the formulated optimal control problem is of large state space and highly nonlinear,an efficient hierarchical initialization technique based on the Dubins-curve method is proposed.Then,a model predictive controller is designed to track the obtained reference trajectory in the presence of initial state error and external disturbances.Numerical experiments demonstrate that the proposed“offline planningþonline tracking”framework can achieve efficient and robust coordinated taxiing planning and tracking even in the presence of initial state error and continuous external disturbances.

Determining the approach speed envelope of carrier aircraft

Many factors,such as deck motion and air wave,influence the determination of the approach speed which has an important effect on landing safety. Until recently,there are no design criteria about approach speed of carrier aircraft in the current standards and available publications. Therefore,the requirements of stall margin, longitudinal acceleration ability,altitude correction and field-of-view on approach speed were researched. Based on the flight dynamics model,the flight simulations were conducted to study the effect of the response time of engine,wave off requirements,elevator efficiency and deflection rate on the approach speed. The results presented that the approach longitudinal acceleration and altitude correction ability had crucial influence on the approach speed envelope of the aircraft. The limitations of the control requirements,field- of- view requirements and gear were also given through the simulation and analysis. Based on the above results,the approach speed envelope were determined.

Path planning for taxi of carrier aircraft launching

Launching efficiency is an important index to measure the fighting capacity of an aircraft carrier. The study on path planning for taxi of carrier aircraft is of great significance for enhancing the launching efficiency. Considering the launching efficiency and the safety in operation of carrier aircraft launching and taking into account the carrier aircraft maneuver performance, deck environment and feature of mission, we proposed a conceptual model which contains the key elements of path planning for taxi of carrier aircraft. Subsequently, the objective function for the path planning problem and its mathematical model containing various constraints were established. With the A * search algorithm, a dynamic weight heuristic function was designed. According to the characteristic of path planning model for taxi of carrier aircraft, a simple and effective detection method was introduced. Finally, a feasible path for taxi of carrier aircraft, which meets the constraints, was presented. Taking the Nimitz-class aircraft carrier as an example, the paths for taxi of carrier aircraft launching from elevators to catapults were planned. Simulation results demonstrated the rationality of the model and the effectiveness of the algorithm.

Obstacle avoidance and path planning for carrier aircraft launching

Abstract Launching safety and efficiency are important indexes to measure the fighting capacity of carrier. The study on path planning for taxi of carrier aircraft launching under actual deck environ ment is of great significance. In actual deck scheduling, manual command is applied to taxi of carrier aircraft, which has negative effects on the safety of staff and carrier aircraft launching. In consideration of both the safety and efficiency of carrier aircraft launching, the key elements of the problem are abstracted based on the analysis of deck environment, carrier aircraft maneuver performance and task requirements. According to the problem description, the mathematical model is established including various constraints. The carrier aircraft and the obstacles are reasonably simplified as circle and polygons respectively. What＇s more, the proposed collision detection model reduces the calculations. Aimed at the features of model, the theory of model predictive control （MPC） is applied to the path search. Then a dynamic weight heuristic function is designed and a dynamic multistep optimization algorithm is proposed. Taking the Nimitz-class aircraft carrier as an example, the paths from parking place to catapult are planned, which indicate the rationality of the model and the effectiveness of the algorithm by comparing the planning results under different simulation environments. The main contribution of research is the establishment of obstacle avoidance and path planning model. In addition, it provides the solution of model and technological foundations for comprehensive command and real-time decision-making of the carrier aircraft.

A review on carrier aircraft dispatch path planning and control on deck

As an important part in sortie/recovery process,the dispatch of carrier aircraft not only affects the sortie/recovery efficiency and safety,but also has severe influence on the carrier's combat efficiency and the comprehensive support capability.Path planning is the key to improve the efficiency and safety during the dispatch process.The main purpose of this paper is to propose a comprehensive investigation of techniques and research progress for the carrier aircraft's dispatch path planning on the deck.Three different dispatch modes of carrier aircraft and the corresponding modeling technologies are investigated,and the aircraft's dispatch path planning techniques and algorithms have been classified into different classes.Moreover,their assumptions and drawbacks have been discussed for single aircraft and multiple aircraft.To make the research work more comprehensive,the corresponding tracking control methodologies are also discussed.Finally,due to the similarity of path planning problem between the carrier aircraft's dispatch and those in other fields,this paper provides an exploratory prospect of the knowledge or method learned from other fields.

Multi-agent Based Hierarchy Simulation Models of Carrier-based Aircraft Catapult Launch

With the aid of multi-agent based modeling approach to complex systems, the hierarchy simulation models of carrier-based aircraft catapult launch are developed. Ocean, carrier, aircraft, and atmosphere are treated as aggregation agents, the detailed components like catapult, landing gears, and disturbances are considered as meta-agents, which belong to their aggregation agent. Thus, the model with two layers is formed i.e. the aggregation agent layer and the meta-agent layer. The information communication among all agents is described. The meta-agents within one aggregation agent communicate with each other directly by information sharing, but the meta-agents, which belong to different aggregation agents exchange their information through the aggregation layer first, and then perceive it from the sharing environment, that is the aggregation agent. Thus, not only the hierarchy model is built, but also the environment perceived by each agent is specified. Meanwhile, the problem of balancing the independency of agent and the resource consumption brought by real-time communication within multi-agent system （MAS） is resolved. Each agent involved in carrier-based aircraft catapult launch is depicted, with considering the interaction within disturbed atmospheric environment and multiple motion bodies including carrier, aircraft, and landing gears. The models of reactive agents among them are derived based on tensors, and the perceived messages and inner frameworks of each agent are characterized. Finally, some results of a simulation instance are given. The simulation and modeling of dynamic system based on multi-agent system is of benefit to express physical concepts and logical hierarchy clearly and precisely. The system model can easily draw in kinds of other agents to achieve a precise simulation of more complex system. This modeling technique makes the complex integral dynamic equations of multibodies decompose into parallel operations of single agent, and it is convenient to expand, maintain, and reuse the program codes.

Exploring mission planning method for a team of carrier aircraft launching

High-level efficiency and safety are of great significance for improving the fighting capability of an aircraft carrier. One way to enhance efficiency and safety level is to organize the carrier aircraft into combat effectively. This paper studies the mission planning problem for a team of carrier aircraft launching, and a novel distributed mission planning architecture is proposed. The architecture is hierarchical and is comprised of four levels, namely, the input level, the coordination level,the path planning level and the execution level. Realistic constraints in each level of the distributed architecture, such as the vortex flow effect, the crowd effect and the motion of aircraft, are considered in the model. To solve this problem, a distributed path planning algorithm based on the asynchronous planning strategy is developed. The proposed Mission Planning Approach for Carrier Aircraft Launching(MPACAL) is validated using the setups of the Nimitz-class aircraft carrier.Compared to the isolated planning architecture and the centralized planning architecture, the proposed distributed planning architecture has advantages in coordinating the launch tasks not only belonging to the same catapult but also when all different catapults are considered. The proposed MPACAL provides a modeling method for the flight deck operation on aircraft carrier.

Guidance and Control Techniques of Carrier-Based Aircraft for Automatic Carrier Landing

We summarize the guidance and control techniques of automatic carrier landing for carrier-based aircraft.First,we analyze the carrier landing operations of the manned fixed-wing aircraft,unmanned fixed-wing aircraft and helicopters.Second,we look into the navigation and guidance system and the flight control methods for current different aircraft.Finally,we draw several conclusions of the development prospects for aircraft carrier landing,including the precision landing control techniques,precision approach and landing guidance techniques,and adaptive,reconfigurable and intelligent flight control techniques.

Modeling of Carrier-based Aircraft Ski Jump Take-off Based on Tensor

A general mathematical model of carrier-based aircraft ski jump take-off is derived based on tensor. The carrier, the aircraft body and the movable parts of the landing gears are treated as independent entities. These entities are assembled into a multi-rigid-body system with flexible links. Dynamical equations of each entity are derived on the basis of the Newton law and the Euler transformation. Using the invariance property of the tensor, the dynamical and kinematical equations are converted to tensor forms which are invariant under time-dependent coordinate transformations. Then the tensor-formed equations are expressed by the matrix operation. Differential equation group of the matrix form is formulated for the programming. The closure of the model is discussed, and the simulation results are given.

Parameter Optimization of Nose Landing Gear Considering Both Take-off and Landing Performance of Catapult Take-off Carrier-Based Aircraft

Optimization of the parameters of landing gear systems with double-stage air springs of catapult take-off carrier-based aircraft is here studied based on the mathematical equations of the classic dual mass spring-damper dynamic model.Certain standards for both take-off and landing performance are put forward.The contradictory factors between take-off and landing processes are analyzed.The optimization of oil in the pin area and the area near the rear oil hole is performed.Then these optimized parameters are used to assess the influence of the initial pressure of the low chamber,the ratio of the high chamber to the low chamber,and the tire inflation pressure on the performance of arresting landing and catapult take-off.The influences of these parameters on carrier-based aircraft and the aircraft-carrier on aircraft catapult take-off is also assessed.Based on the results of the simulation,respective take-off criteria must be drafted considering different types of aircraft and different take-off load cases,all of which must be matched to parameters relevant to catapult take-off.

Winning Probability Estimation Based on Improved Bradley-Terry Model and Bayesian Network for Aircraft Carrier Battle

To provide a decision-making aid for aircraft carrier battle,the winning probability estimation based on Bradley-Terry model and Bayesian network is presented. Firstly,the armed forces units of aircraft carrier are classified into three types,which are aircraft,ship and submarine. Then,the attack ability value and defense ability value for each type of armed forces are estimated by using BP neural network,whose training results of sample data are consistent with the estimation results. Next,compared the assessment values through an improved Bradley-Terry model and constructed a Bayesian network to do the global assessment,the winning probabilities of both combat sides are obtained. Finally,the winning probability estimation for a navy battle is given to illustrate the validity of the proposed scheme.

Dynamics Analysis of Carrier-Based Aircraft with Off-Center Catapult Launch

In order to enhance the safety of the catapult launch of the carrier-based aircraft,the catapult launch multibody dynamic model is established aiming at the problem of off center catapult launch.The whole catapult process including four stages which are buffering,tensioning,releasing and taxiing is taken into consideration and the body dynamics of the off-center catapult during each stage is analyzed.The catapult launch dynamic differences between the conditions only considering taxiing and that considering four stages are compared,and the effects of the different initial off center distances considering four stages on the attitude,landing gear load and acceleration of the carrier based aircraft during catapult launch are discussed.The results show that only considering taxiing may underestimate the dynamics of the carrier-based aircraft substantially.When taking four stages into consideration,the initial off-center distance has small influence on the aircraft dynamic characteristics during buffering and tensioning but has larger influence on that during releasing and taxiing.The increase of the off-center distance will cause the enhancement of the aircraft rolling and yawing,which may lead to the load difference between the left and right landing gears and the increase of the aircraft lateral acceleration.The establishment and simulation of the catapult launch multi body dynamic model founded on buffering,tensioning,releasing and taxiing provide reference for the carrier-based aircraft design and analysis of the catapult launch dynamics.

Optimal Preview Control for Automatic Carrier Landing System of Carrier-Based Aircraft with Air Wake

Carrier-based aircraft carrier landing is a special kind of tracking control problem and not suitable for classical control methods,which may miss the desired performance or result in overdesign.Therefore,we present an optimal preview control for automatic carrier landing system(ACLS)by using state information of system,as well as future reference information,which can avoid the shortcomings of classical control methods.Since the flight performance of carrier-based aircraft is disturbed by air wake when the aircraft flies near the area of carrier stern,we design a disturbance rejection strategy to ensure that aircraft track the glide path with high precision and robustness.Further,carrier-based aircraft is a complex nonlinear system.However,the nonlinear model of carrier-based aircraft can be linearized at equilibrium landing state and decoupled into the longitudinal model and the lateral model.Therefore,an optimal preview control system is designed.The simulation results of a carrier-based aircraft show that the optimal preview control system can effectively suppress air wake.Tracking accuracy of optimal preview controller is higher than that of the proportional integral differential(PID)control system.

Linear random search and engineering estimation of sinkage for launching carrier aircraft

A linear random search algorithm(LRSA) is developed to determine the critical value of takeoff weight limited to the safe flight track sinkage and an engineering estimation method(EEM) is proposed to calculate the sinkage of carrier aircraft launch in real time. Based on the analysis of free flight after leaving the carrier, the equations are established to participate into engineering estimation of flight track sinkage. Thanks to the proposed search algorithm, the maximum takeoff weight of carrier aircraft with safe catapult launch flight track sinkage is generated in few steps. The results of sinkage estimation and the search algorithm are in good agreement with that of aircraft catapult launch simulation. The main contribution of this manuscript is the establishment of simple and accurate engineering estimation for carrier aircraft launch flight track sinkage and the development of robust and efficient search algorithm for the critical value with safe catapult criteria.

基于分阶段自编码器与注意力机制的舰载机着舰航迹实时预测模型

航空母舰舰载机着舰过程中应沿相对固定的航迹下滑,以保证触舰点位于舰艉拦阻系统所在的区域,因此舰载机航迹是着舰信号官进行指挥决策的重要依据之一。舰载机航迹实时预测有助于着舰信号官判断着舰作业发展态势,及时形成正确的航迹纠偏引导指令。为此,提出一种基于分阶段自编码器与注意力机制的着舰航迹实时预测模型。第一阶段采用降噪自编码器对历史航迹数据进行特征提取;第二阶段基于长短期记忆网络构建时序自编码器,同时引入注意力机制对不同时刻的编码器输出分配不同的权重,自适应学习其对最终预测结果的影响强度。通过仿真实验将所提模型与6种基线模型进行对比,结果表明,所提模型的综合性能优于基线模型,能够满足着舰航迹实时准确预测的应用需求。

舰载机前起落架缓冲性能参数敏感性研究

为了同时满足缓冲和突伸性能,舰载机前起落架常采用双腔缓冲器设计。以某型机前起落架为研究对象,建立前起落架缓冲性能分析动力学模型,并将仿真计算结果与试验结果进行验证对比,验证理论模型的有效性和正确性。对缓冲器高、低压腔初始压力以及体积占比进行参数敏感性分析。结果表明,高、低压腔初始充填压力和体积占比对起落架缓冲性能的影响有别于它们对突伸性能的影响,所以对舰载机前起落架缓冲器的设计需不断优化,同时兼顾缓冲和突伸性能。

不同海况条件下舰载无人机着舰安全分析

针对无人机上舰的使用需求,本文对舰载无人机着舰开展了系统的研究。建立了机-舰-环境综合模型和舰载无人机全自动着舰引导控制系统;基于建立的舰载无人机着舰综合模型对不同海况下的着舰过程进行仿真分析,研究不同海况条件以及航母不同航速和遭遇角对着舰安全的影响。仿真研究表明:在复杂海况下,航母可通过适当提高航速以获得更高的着舰成功率,但过高的航速会导致舰尾流扰动加剧,使得着舰成功率显著下降;通过对仿真结果进行统计分析,给出了不同海况下的着舰安全范围,为无人机着舰辅助决策提供参考。

抗阻训练对航母舰载机飞行学员颈部疼痛和颈部功能的影响

目的通过运动疗法和颈肌抗阻训练改善飞行员颈部功能,研究抗阻训练对舰母载机飞行学员颈部疼痛水平和表面肌电活动的影响。方法对航母舰载机飞行学员进行颈部疼痛干预实验,实验周期为3个月。纳入23~35岁的男性舰载机飞行学员,运动前进行健康筛查和风险评估,排除高风险人群。发放调查问卷,包括颈椎功能障碍指数表和中国体力活动调查表。进行颈肌功能测试,包括颈肌最大肌力、颈椎关节活动度和表面肌电。将实验对象随机分为两组,每组各8名。第一组为对照组,每天照常进行部队安排的训练;第二组为抗阻训练组,在照常进行部队安排训练的基础上使用自主研发的舰载机飞行员用颈椎病预防训练器,制订有针对性的训练方案。每周进行3次抗阻训练,每次训练时间为20 min,在干预实验结束时再次测试颈肌最大肌力、颈椎关节活动度和表面肌电值。将所有数据导入SPSS 22.0软件,结果采用平均值±标准差(x±s)表示,以P<0.05为差异具有统计学意义。结果(1)干预3个月后,抗阻训练对视觉疼痛模拟评分(VAS)的影响效果显著。(2)干预后受试者颈椎功能障碍指数(NDI)的自身前后测试结果表明,其颈椎功能障碍水平得到明显好转。(3)干预后,受试者自身关节活动度的组间对比结果显示,抗阻训练组受试者的前屈、后伸、左屈、右屈、左旋和右旋的自身变化差值比较,差异具有统计学意义(P<0.05)。(4)干预后,两组受试者的自身颈部肌力结果显示,抗阻训练组受试者的六个动作自身变化差值比较,差异无统计学意义(P>0.05)。(5)干预前后在前屈、后伸、左屈、右屈四个动作测试中抗阻训练组的均方根值(RMS)结果显示,左右胸锁乳突肌和左右侧斜方肌上束的差异均无统计学意义(P>0.05)。(6)干预前后在前屈、后伸、左屈、右屈四个动作测试中抗阻训练组的积分肌电值(iEMG)结果显示,左右胸锁乳突肌和左右侧斜方肌上束的差异均无统计学意义(P>0.05)。结论接受3个月抗阻训练可有效缓解舰载机飞行学员的颈部疼痛,改善颈椎功能障碍以及颈部被测四块肌肉深浅肌纤维的载荷,增强颈部肌肉力量、抗疲劳能力和颈部关节活动度,优化颈部深浅层肌肉的激活模式。

羽毛球运动训练对航母舰载机飞行学员颈痛的干预效果研究

目的评估羽毛球运动对舰载机飞行学员颈痛的干预效果,为该运动预防和缓解舰载机飞行学员颈痛提供科学依据。方法根据纳入和排除标准筛选16名航母舰载机飞行学员作为受试者,随机分为运动康复组和对照组,每组各8人。运动康复组除进行部队日常训练外,另进行每周3次,每次1 h的羽毛球运动;对照组进行部队日常训练,不做其他干预。研究为期3个月。颈痛的干预效果以实验前后颈椎功能障碍指数(NDI)评分、视觉模拟疼痛量表(VAS)、颈椎活动度(CROM)、颈部最大肌力、表面肌电信号均方根值(RMS)、积分肌电值(iEMG)作为评价指标。结果运动康复组NDI评分较干预前具有显著性差异(P<0.05),对照组NDI评分较干预前无显著性差异(P>0.05)。运动康复组VAS评分较干预前有显著性差异(P<0.01),对照组VAS评分较干预前无显著性差异(P>0.05)。运动康复组受试者干预后颈椎最大活动度在各方向均有所增加,且左屈、右屈活动度较干预前具有显著性差异(P<0.05),其余方向无显著性差异(P>0.05);对照组颈椎各方向最大活动度较干预前无显著性差异(P>0.05)。运动康复组受试者颈部最大肌力在前屈、后伸、左屈方向较干预前具有显著性差异(P<0.01),右屈、左旋、右旋值较干预前具有显著性差异(P<0.05);左右侧胸锁乳突肌RMS在四个方向动作中无显著性差异(P>0.05),左侧斜方肌上束在前屈和右屈动作中RMS具有显著性差异(P<0.05),在后伸和左屈动作中无显著性差异(P>0.05),右侧斜方肌上束在四个方向动作中无显著性差异(P>0.05)。运动康复组受试者干预后在前屈、后伸以及右屈运动中,4块肌肉iEMG均大于干预前,但无显著性差异(P>0.05)。在左屈动作中,左侧胸锁乳突肌与右侧斜方肌上束iEMG大于干预后,右侧胸锁乳突肌和左侧斜方肌上束iEMG小于干预后,但均无显著性差异(P>0.05)。结论羽毛球运动干预能够缓解航母舰载机飞行学员的颈部疼痛,使其颈椎功能障碍得到一定程度的恢复,并且能够增加颈部灵活性,增强颈部肌力,同时激活深层肌肉参与维持颈部稳定,有效提升颈部肌肉群的抗疲劳能力。