In this paper,we propose a cooperative guidance law aimed to achieve coordinated impact angles with limited observation on target information.The primary challenge lies in establishing an appropriate communication gra...In this paper,we propose a cooperative guidance law aimed to achieve coordinated impact angles with limited observation on target information.The primary challenge lies in establishing an appropriate communication graph among all missiles and devising an algorithm to estimate target acceleration information during engagements.To address this,we propose a specific communication topology and employ a numerical integration-based estimation method.Additionally,a distributed algorithm is introduced to facilitate consensus on target acceleration estimation.Building upon these foundations,we design an optimal-control-based distributed guidance law for each missile.Performance of the proposed guidance law is validated through numerical simulations.展开更多
The capturability of the Three-Dimensional(3D)Realistic True Proportional Navigation(RTPN)guidance law is thoroughly analyzed.The true-arbitrarily maneuvering target is considered,which maneuvers along an arbitrary di...The capturability of the Three-Dimensional(3D)Realistic True Proportional Navigation(RTPN)guidance law is thoroughly analyzed.The true-arbitrarily maneuvering target is considered,which maneuvers along an arbitrary direction in 3D space with an arbitrary but upperbounded acceleration.The whole nonlinear relative kinematics between the interceptor and target is taken into account.First,the upper-bound of commanded acceleration of 3D RTPN is deduced,using a novel Lyapunov-like approach.Second,the reasonable selection range of navigation gain of3D RTPN is analyzed,when the maneuver limitation of interceptor is considered.After that,a more realistic definition of capture is adopted,i.e.,the relative range is smaller than an acceptable miss-distance while the approaching speed is larger than a required impact speed.Unlike previous researches which present Two-Dimensional(2D)capture regions,the inequality analysis technique is utilized to obtain the 3D capture region,where the three coordinates are the closing speed,transversal relative speed,and relative range.The obtained capture region could be taken as a sufficient-but-unnecessary condition of capture.The new theoretical findings are all given in explicit expressions and are more general than previous results.展开更多
For the maintenance of the pipelines which pipe oil from oil fields in the Bohai Gulf of China, an underwater vehicle for pipeline detection and maintenance （PDM-UV） is designed. In this paper, the maneuverability a...For the maintenance of the pipelines which pipe oil from oil fields in the Bohai Gulf of China, an underwater vehicle for pipeline detection and maintenance （PDM-UV） is designed. In this paper, the maneuverability and motion simulation of PDM-UV are studied. A general dynamic equation to describe the hydrodynamics of PDM-UV is presented. For a deep understanding of the dynamics of PDM-UV, which is somewhat different from normal underwater vehicles in configuration, the maneuverability is discussed in terms of hydrodynamic coefficients with experimental results. Finally, the whole motion simulation system is introduced and simulation results are presented to demonstrate the feasibility and correctness of the simulation platform.展开更多
In this paper,the mechatronic design and maneuverability analysis of a novel robotic shark are presented.To obtain good maneuverability,a barycenter regulating device is designed to assist the posture adjustment at lo...In this paper,the mechatronic design and maneuverability analysis of a novel robotic shark are presented.To obtain good maneuverability,a barycenter regulating device is designed to assist the posture adjustment at low speeds.Based on the Newton-Euler approach,an analytical dynamic model is established with particular consideration of pectoral fins for threedimensional motions.The hydrodynamic coefficients are computed using computational fluid dynamics(CFD)methods.Oscillation amplitudes and phases are determined by fitting an optimized fish body wave.The performance of the robotic shark is estimated by varying the oscillation frequency and offset angle.The results show that with oscillation frequency increasing,the swimming speed increases linearly.The robotic shark reaches the maximum swimming speed of 1.05 m/s with an oscillation frequency of 1.2 Hz.Furthermore,the turning radius decreases nonlinearly as the offset angle increased.The robotic shark reaches the minimum turning radius of 1.4 times the body length with 0.2 Hz frequency and 12°offset angle.In the vertical plane,as the pectoral fin angle increases,the diving velocity increases nonlinearly with increase rate slowing down.展开更多
Maneuverability is one of the most important sailing performances of vessels. In this article, a motion control model with three degrees of freedom(DoFs) for twin-waterjet propulsion vessel is proposed. The model is d...Maneuverability is one of the most important sailing performances of vessels. In this article, a motion control model with three degrees of freedom(DoFs) for twin-waterjet propulsion vessel is proposed. The model is developed on the basis of maneuvering model group(MMG) maneuverability equations. A simulation environment is constructed on the Matlab Simulink platform. Standard turning tests and zig-zag tests are simulated by solving the motion control model, and the corresponding maneuverability parameters are calculated. Simulation results demonstrate that the maneuverability parameters are in accordance with the vessel maneuverability standard.The approach may be applied to the rapid prediction of vessel maneuverability.展开更多
In order to simulate the under water motion of a mini autonomous underwater vehicle( AUV) and an- alyze its maneuverability,the dynamical characteristic of the mini AUV was researched. The 6-DOF motion equations were ...In order to simulate the under water motion of a mini autonomous underwater vehicle( AUV) and an- alyze its maneuverability,the dynamical characteristic of the mini AUV was researched. The 6-DOF motion equations were founded. Through model experiment with accessory bodies,the hydrodynamics of AUV body including resistance,main inertial and viscous hydrodynamic coefficients was obtained. The hydrodynamics of rudders was gained through theoretical calculation. Simulation computation of the vehicle was carried out through numerical integration of the motion equations. A motion simulation system was constructed. Four typical maneuvers in horizontal and vertical planes were simulated and the maneuverability of the mini AUV was forecasted. The simulation results reflect the basic motion characteristic of mini AUV and validate the feasibility and correctness of the whole system. The simulation system can be a testing platform for the design and debugging of motion controller and an effective tool for the development of AUV.展开更多
Ordinary mobile robots have some kind of moving mechanisms attached to one rigid body. When working on rough terrain or in other hazard environments, there existed some possibilities that the robot will be turned up s...Ordinary mobile robots have some kind of moving mechanisms attached to one rigid body. When working on rough terrain or in other hazard environments, there existed some possibilities that the robot will be turned up side down, thus causing losses to the robot's expedition. Multi bodied mobile robots provide a solution to that problem. Using active joints between bodies, the robot can recover from turnover situation by itself. In this paper, the authors discuss the joint arrangements and the additional maneuverability resulted from joints between body segments.展开更多
It is well known that model test is one of approaches to investigate the maneuverability of vessels and the correlative method is an important problem of model test for vessels with large scale. Some of correlative pr...It is well known that model test is one of approaches to investigate the maneuverability of vessels and the correlative method is an important problem of model test for vessels with large scale. Some of correlative problems,which should be solved with care in model test,are presented from analysis of the similarity principle for the ship maneuverability in this paper.A corrective method of appropriate angle of rudder is provided based on the result of maneuverability model test for a tanker with large scale and the corresponding prediction of the maneuverability for full scale tanker is satisfactory in view of engineering practice.展开更多
The problem of collision avoidance for non-cooperative targets has received significant attention from researchers in recent years.Non-cooperative targets exhibit uncertain states and unpredictable behaviors,making co...The problem of collision avoidance for non-cooperative targets has received significant attention from researchers in recent years.Non-cooperative targets exhibit uncertain states and unpredictable behaviors,making collision avoidance significantly more challenging than that for space debris.Much existing research focuses on the continuous thrust model,whereas the impulsive maneuver model is more appropriate for long-duration and long-distance avoidance missions.Additionally,it is important to minimize the impact on the original mission while avoiding noncooperative targets.On the other hand,the existing avoidance algorithms are computationally complex and time-consuming especially with the limited computing capability of the on-board computer,posing challenges for practical engineering applications.To conquer these difficulties,this paper makes the following key contributions:(A)a turn-based(sequential decision-making)limited-area impulsive collision avoidance model considering the time delay of precision orbit determination is established for the first time;(B)a novel Selection Probability Learning Adaptive Search-depth Search Tree(SPL-ASST)algorithm is proposed for non-cooperative target avoidance,which improves the decision-making efficiency by introducing an adaptive-search-depth mechanism and a neural network into the traditional Monte Carlo Tree Search(MCTS).Numerical simulations confirm the effectiveness and efficiency of the proposed method.展开更多
This paper presents the design of an asymmetrically variable wingtip anhedral angles morphing aircraft,inspired by biomimetic mechanisms,to enhance lateral maneuver capability.Firstly,we establish a lateral dynamic mo...This paper presents the design of an asymmetrically variable wingtip anhedral angles morphing aircraft,inspired by biomimetic mechanisms,to enhance lateral maneuver capability.Firstly,we establish a lateral dynamic model considering additional forces and moments resulting during the morphing process,and convert it into a Multiple Input Multiple Output(MIMO)virtual control system by importing virtual inputs.Secondly,a classical dynamics inversion controller is designed for the outer-loop system.A new Global Fast Terminal Incremental Sliding Mode Controller(NDO-GFTISMC)is proposed for the inner-loop system,in which an adaptive law is implemented to weaken control surface chattering,and a Nonlinear Disturbance Observer(NDO)is integrated to compensate for unknown disturbances.The whole control system is proven semiglobally uniformly ultimately bounded based on the multi-Lyapunov function method.Furthermore,we consider tracking errors and self-characteristics of actuators,a quadratic programmingbased dynamic control allocation law is designed,which allocates virtual control inputs to the asymmetrically deformed wingtip and rudder.Actuator dynamic models are incorporated to ensure physical realizability of designed allocation law.Finally,comparative experimental results validate the effectiveness of the designed control system and control allocation law.The NDO-GFTISMC features faster convergence,stronger robustness,and 81.25%and 75.0%reduction in maximum state tracking error under uncertainty compared to the Incremental Nonlinear Dynamic Inversion Controller based on NDO(NDO-INDI)and Incremental Sliding Mode Controller based on NDO(NDO-ISMC),respectively.The design of the morphing aircraft significantly enhances lateral maneuver capability,maintaining a substantial control margin during lateral maneuvering,reducing the burden of the rudder surface,and effectively solving the actuator saturation problem of traditional aircraft during lateral maneuvering.展开更多
In this paper,we present an overview of the mechanical design and control of biomimetic robotic fishes with high maneuverability.The robotic fishes modelled after Esoxlucius adopt multilink propulsive mechanism for a ...In this paper,we present an overview of the mechanical design and control of biomimetic robotic fishes with high maneuverability.The robotic fishes modelled after Esoxlucius adopt multilink propulsive mechanism for a high turning rate and a small turning radius.According to different tasks,these robotic fishes are designed with decorated pectoral fins for a two-dimensional horizon plane,or controllable pectoral fins with multiple degrees of freedom for a three-dimensional space.Through observing and analyzing the fast-starts of real fish,we separately develop a dynamic trajectory tracking strategy based C-start control method and an L-shaped sliding method based S-start control method.Finally,a four-link robotic fish is able to execute C-start flexibly with a turning angle of up to 213°,a top turning rate of approximately670°/s,and an upper limit of turning precision of less than 10°and an S-start with a peak turning rate up to318.08±9.20°/s.The experimental results verify the feasibility of our high-maneuverability-oriented mechatronic design and control methods.展开更多
Muscle Shortening Maneuver(MSM)is a rehabilitation technique successfully applied to several pathological conditions.The concept is to passively elongate and shorten the target muscle group of the affected limb.As a r...Muscle Shortening Maneuver(MSM)is a rehabilitation technique successfully applied to several pathological conditions.The concept is to passively elongate and shorten the target muscle group of the affected limb.As a result,the functionality(muscle strength and range of motion)of that limb is improved.The existing system induces these oscillations manually or without any feedback control,which can compromise the effectiveness and standardization of MSM.In this paper,we present a mechatronic system that can precisely deliver motion oscillations to the upper limb for a controllable execution of MSM.First,we collected the parameters(frequency and amplitude of the oscillations)from a system where a motor was heuristically used by a well-experienced therapist to induce the oscillations(without any feedback control).Based on these specifications,we chose the motor and rebuilt the experimental setup,implementing a sliding mode control with a sliding perturbation observer.With our system,the operator can choose a given frequency and amplitude of the oscillations within the range we experimentally observed.We tested our system with ten participants of different anthropometry.We found that our system can accurately reproduce oscillations in the frequency range 0.8 to 1.2 Hz and amplitude range 2 to 6 cm,with a maximum percentage normalized root mean square error around 7%.展开更多
1) Introduction: Ventilation disorders of the middle ear play a major role in everyday clinical ENT-practice and sometimes represent a major therapeutic challenge. In addition to the conventional therapy of tympanosto...1) Introduction: Ventilation disorders of the middle ear play a major role in everyday clinical ENT-practice and sometimes represent a major therapeutic challenge. In addition to the conventional therapy of tympanostomy tube insertion, tuboplasty (TP) offers a less invasive option for treating this problem. The study should examine whether TP can be performed in a rural setting. 2) Material and methods: This is a prospective, monocentric study of patients scheduled for TP because of tubal ventilation disorder (TVD) in a rural region of Germany. The diagnosis was established after a thorough clinical examination and by assessing the possibility of performing the Valsalva maneuver, the tympanogram type, recording the middle ear pressure and air-bone gap. The subjective impairment caused by the TVD was evaluated using the EDTQ-7 questionnaire pre- and approximately 3 months postoperatively. 3) Results: Sixty-two patients with 92 TP were included with a mean age of 44.1 years. The EDTQ-7 score decreased highly significantly from 3.6 to 1.7 (p < 0.0001) without correlating with parameters such as age, sex, BMI, allergies or smoking. Middle ear pressure fell in average by −87 daPa, resulting in an improvement of the tympanogram type. The preoperative air-bone gap of 10.2 dB also was reduced significantly in most patients to 8.0 dB after the procedure. No notable complications occurred beside a sore throat due to the use of a laryngeal mask for ventilation during anesthesia in two cases. 4) Conclusion: In our experience, TP represents a less invasive and, in many cases, successful alternative to the established tympanostomy tube insertion with the advantage of an intact eardrum. It can also be offered and successfully performed in a rural setting.展开更多
The concept of the spacecraft Reachable Domain(RD)has garnered significant scholarly attention due to its crucial role in space situational awareness and on-orbit service applications.While the existing research has l...The concept of the spacecraft Reachable Domain(RD)has garnered significant scholarly attention due to its crucial role in space situational awareness and on-orbit service applications.While the existing research has largely focused on single-impulse RD analysis,the challenge of Multi-Impulse RD(MIRD)remains a key area of interest.This study introduces a methodology for the precise calculation of spacecraft MIRD.The reachability constraints specific to MIRD are first formulated through coordinate transformations.Two restricted maneuvering strategies are examined.The derivation of two extremum conditions allows for determining the accessible orientation range and the nodes encompassing the MIRD.Subsequently,four nonlinear programming models are developed to address two types of MIRD by skillfully relaxing constraints using scale factors.Numerical results validate the robustness and effectiveness of the proposed approach,showing substantial agreement with Monte Carlo simulations and confirming its applicability to spacecraft on various elliptical orbits.展开更多
1 The grandfather was choking on a mouthful of food,unable to breathe and unable to cough.The grandson,recalling the important lesson learned during the 8-13 Project organized by the Italian Red Cross⁃Poggi⁃Sermide Co...1 The grandfather was choking on a mouthful of food,unable to breathe and unable to cough.The grandson,recalling the important lesson learned during the 8-13 Project organized by the Italian Red Cross⁃Poggi⁃Sermide Committee,suggested performing the Heimlich manoeuvre(海姆立克急救法)on the elderly man.展开更多
Aiming at the missile avoidance problem of the unmanned aerial vehicle(UAV)in complex obstacle environments,this work proposes a collision-avoidance method based on receding horizon optimization.The proposed method ge...Aiming at the missile avoidance problem of the unmanned aerial vehicle(UAV)in complex obstacle environments,this work proposes a collision-avoidance method based on receding horizon optimization.The proposed method generated a specific trajectory for the UAV to effectively induce the proportional navigation missile to successfully intercept the obstacle,thereby accomplishing the evasive maneuver.The evasive maneuver was divided into two distinct stages,namely the collision-inducing phase and the fast departure phase.The obstacle potential field-based target selection algorithm was employed to identify the most appropriate target obstacle,while the induced trajectory was determined through a combination of receding horizon optimization and the hp-adaptive pseudo-spectral method.Simulation experiments were carried out under three different types of obstacle environments and one multiobstacle environment,and the simulation results show that the method proposed in this paper greatly improves the success rate of UAV evasive maneuvers,proving the effectiveness of this method.展开更多
In order to enhance the penetration performance of hypersonic gliding vehicle,a chaotification method of gliding midcourse based on flight dynamics is proposed.Firstly,a chaotic series⁃based angle of attack(AOA)contro...In order to enhance the penetration performance of hypersonic gliding vehicle,a chaotification method of gliding midcourse based on flight dynamics is proposed.Firstly,a chaotic series⁃based angle of attack(AOA)control algorithm and an AOA switching control algorithm considering flight altitude are proposed in this study based on a simple chaotic system with considerations of AOA constraints and process constraints.Secondly,the Lyapunov exponent Algorithm Of Continuous system is applied to verify the chaotic characteristic of flight trajectories.Thirdly,a stability region analysis method is proposed based on a conservative dynamics,which can be applied to the stability region analysis of general complex dynamics.Finally,the simulations show that both control algorithms can realize the chaotification of trajectories,and the flight trajectories obtained by the AOA switching control algorithm are feasible.展开更多
The paper presents a two-layer,disturbance-resistant,and fault-tolerant affine formation maneuver control scheme that accomplishes the surrounding of a dynamic target with multiple underactuated Quadrotor Unmanned Aer...The paper presents a two-layer,disturbance-resistant,and fault-tolerant affine formation maneuver control scheme that accomplishes the surrounding of a dynamic target with multiple underactuated Quadrotor Unmanned Aerial Vehicles(QUAVs).This scheme mainly consists of predefinedtime estimators and fixed-time tracking controllers,with a hybrid Laplacian matrix describing the communication among these QUAVs.At the first layer,we devise predefined time estimators for leading and following QUAVs,enabling accurate estimation of desired information.In the second layer,we initially devise a fixed-time hybrid observer to estimate unknown disturbances and actuator faults.Fixedtime translational tracking controllers are then proposed,and the intermediary control input from these controllers is used to extract the desired attitude and angular velocities for the fixed-time rotational tracking controllers.We employ an exact tracking differentiator to handle variables that are challenging to differentiate directly.The paper includes a demonstration of the control system stability through mathematical proof,as well as the presentation of simulation results and comparative simulations.展开更多
This paper investigates impulsive orbital attack-defense(AD)games under multiple constraints and victory conditions,involving three spacecraft:attacker,target,and defender.In the AD scenario,the attacker aims to breac...This paper investigates impulsive orbital attack-defense(AD)games under multiple constraints and victory conditions,involving three spacecraft:attacker,target,and defender.In the AD scenario,the attacker aims to breach the defender's interception to rendezvous with the target,while the defender seeks to protect the target by blocking or actively pursuing the attacker.Four different maneuvering constraints and five potential game outcomes are incorporated to more accurately model AD game problems and increase complexity,thereby reducing the effectiveness of traditional methods such as differential games and game-tree searches.To address these challenges,this study proposes a multiagent deep reinforcement learning solution with variable reward functions.Two attack strategies,Direct attack(DA)and Bypass attack(BA),are developed for the attacker,each focusing on different mission priorities.Similarly,two defense strategies,Direct interdiction(DI)and Collinear interdiction(CI),are designed for the defender,each optimizing specific defensive actions through tailored reward functions.Each reward function incorporates both process rewards(e.g.,distance and angle)and outcome rewards,derived from physical principles and validated via geometric analysis.Extensive simulations of four strategy confrontations demonstrate average defensive success rates of 75%for DI vs.DA,40%for DI vs.BA,80%for CI vs.DA,and 70%for CI vs.BA.Results indicate that CI outperforms DI for defenders,while BA outperforms DA for attackers.Moreover,defenders achieve their objectives more effectively under identical maneuvering capabilities.Trajectory evolution analyses further illustrate the effectiveness of the proposed variable reward function-driven strategies.These strategies and analyses offer valuable guidance for practical orbital defense scenarios and lay a foundation for future multi-agent game research.展开更多
基金supported by the NSFC 62088101 Autonomous Intelligent Unmanned Systems,Chinaby the Zhejiang Provincial Natural Science Foundation of China(No.LR20F030003).
文摘In this paper,we propose a cooperative guidance law aimed to achieve coordinated impact angles with limited observation on target information.The primary challenge lies in establishing an appropriate communication graph among all missiles and devising an algorithm to estimate target acceleration information during engagements.To address this,we propose a specific communication topology and employ a numerical integration-based estimation method.Additionally,a distributed algorithm is introduced to facilitate consensus on target acceleration estimation.Building upon these foundations,we design an optimal-control-based distributed guidance law for each missile.Performance of the proposed guidance law is validated through numerical simulations.
基金supported in part by the National Natural Science Foundation of China(No.12002370)in part by the Hunan Provincial Natural Science Foundation of China(No.2019JJ50736)。
文摘The capturability of the Three-Dimensional(3D)Realistic True Proportional Navigation(RTPN)guidance law is thoroughly analyzed.The true-arbitrarily maneuvering target is considered,which maneuvers along an arbitrary direction in 3D space with an arbitrary but upperbounded acceleration.The whole nonlinear relative kinematics between the interceptor and target is taken into account.First,the upper-bound of commanded acceleration of 3D RTPN is deduced,using a novel Lyapunov-like approach.Second,the reasonable selection range of navigation gain of3D RTPN is analyzed,when the maneuver limitation of interceptor is considered.After that,a more realistic definition of capture is adopted,i.e.,the relative range is smaller than an acceptable miss-distance while the approaching speed is larger than a required impact speed.Unlike previous researches which present Two-Dimensional(2D)capture regions,the inequality analysis technique is utilized to obtain the 3D capture region,where the three coordinates are the closing speed,transversal relative speed,and relative range.The obtained capture region could be taken as a sufficient-but-unnecessary condition of capture.The new theoretical findings are all given in explicit expressions and are more general than previous results.
基金The paper was supported bythe National Ocean 863 High Technology Project (Grant No.2001AA602021)
文摘For the maintenance of the pipelines which pipe oil from oil fields in the Bohai Gulf of China, an underwater vehicle for pipeline detection and maintenance （PDM-UV） is designed. In this paper, the maneuverability and motion simulation of PDM-UV are studied. A general dynamic equation to describe the hydrodynamics of PDM-UV is presented. For a deep understanding of the dynamics of PDM-UV, which is somewhat different from normal underwater vehicles in configuration, the maneuverability is discussed in terms of hydrodynamic coefficients with experimental results. Finally, the whole motion simulation system is introduced and simulation results are presented to demonstrate the feasibility and correctness of the simulation platform.
基金financially supported by the National Natural Science Foundation of China(Grant No.51909040)the Natural Science Foundation of Heilongjiang Province(Grant No.LH2020E073)the Key Technology Research and Development Program of Shandong(Grant No.2020CXGC010702).
文摘In this paper,the mechatronic design and maneuverability analysis of a novel robotic shark are presented.To obtain good maneuverability,a barycenter regulating device is designed to assist the posture adjustment at low speeds.Based on the Newton-Euler approach,an analytical dynamic model is established with particular consideration of pectoral fins for threedimensional motions.The hydrodynamic coefficients are computed using computational fluid dynamics(CFD)methods.Oscillation amplitudes and phases are determined by fitting an optimized fish body wave.The performance of the robotic shark is estimated by varying the oscillation frequency and offset angle.The results show that with oscillation frequency increasing,the swimming speed increases linearly.The robotic shark reaches the maximum swimming speed of 1.05 m/s with an oscillation frequency of 1.2 Hz.Furthermore,the turning radius decreases nonlinearly as the offset angle increased.The robotic shark reaches the minimum turning radius of 1.4 times the body length with 0.2 Hz frequency and 12°offset angle.In the vertical plane,as the pectoral fin angle increases,the diving velocity increases nonlinearly with increase rate slowing down.
基金the Open Project of the Key Laboratory of Science and Technology on Waterjet Propulsion(No.614222303051117)the Joint Fund of CSSC(No.6141B03020301)
文摘Maneuverability is one of the most important sailing performances of vessels. In this article, a motion control model with three degrees of freedom(DoFs) for twin-waterjet propulsion vessel is proposed. The model is developed on the basis of maneuvering model group(MMG) maneuverability equations. A simulation environment is constructed on the Matlab Simulink platform. Standard turning tests and zig-zag tests are simulated by solving the motion control model, and the corresponding maneuverability parameters are calculated. Simulation results demonstrate that the maneuverability parameters are in accordance with the vessel maneuverability standard.The approach may be applied to the rapid prediction of vessel maneuverability.
文摘In order to simulate the under water motion of a mini autonomous underwater vehicle( AUV) and an- alyze its maneuverability,the dynamical characteristic of the mini AUV was researched. The 6-DOF motion equations were founded. Through model experiment with accessory bodies,the hydrodynamics of AUV body including resistance,main inertial and viscous hydrodynamic coefficients was obtained. The hydrodynamics of rudders was gained through theoretical calculation. Simulation computation of the vehicle was carried out through numerical integration of the motion equations. A motion simulation system was constructed. Four typical maneuvers in horizontal and vertical planes were simulated and the maneuverability of the mini AUV was forecasted. The simulation results reflect the basic motion characteristic of mini AUV and validate the feasibility and correctness of the whole system. The simulation system can be a testing platform for the design and debugging of motion controller and an effective tool for the development of AUV.
文摘Ordinary mobile robots have some kind of moving mechanisms attached to one rigid body. When working on rough terrain or in other hazard environments, there existed some possibilities that the robot will be turned up side down, thus causing losses to the robot's expedition. Multi bodied mobile robots provide a solution to that problem. Using active joints between bodies, the robot can recover from turnover situation by itself. In this paper, the authors discuss the joint arrangements and the additional maneuverability resulted from joints between body segments.
文摘It is well known that model test is one of approaches to investigate the maneuverability of vessels and the correlative method is an important problem of model test for vessels with large scale. Some of correlative problems,which should be solved with care in model test,are presented from analysis of the similarity principle for the ship maneuverability in this paper.A corrective method of appropriate angle of rudder is provided based on the result of maneuverability model test for a tanker with large scale and the corresponding prediction of the maneuverability for full scale tanker is satisfactory in view of engineering practice.
基金co-supported by the Foundation of Shanghai Astronautics Science and Technology Innovation,China(No.SAST2022-114)the National Natural Science Foundation of China(No.62303378),the National Natural Science Foundation of China(Nos.124B2031,12202281)the Foundation of China National Key Laboratory of Science and Technology on Test Physics&Numerical Mathematics,China(No.08-YY-2023-R11)。
文摘The problem of collision avoidance for non-cooperative targets has received significant attention from researchers in recent years.Non-cooperative targets exhibit uncertain states and unpredictable behaviors,making collision avoidance significantly more challenging than that for space debris.Much existing research focuses on the continuous thrust model,whereas the impulsive maneuver model is more appropriate for long-duration and long-distance avoidance missions.Additionally,it is important to minimize the impact on the original mission while avoiding noncooperative targets.On the other hand,the existing avoidance algorithms are computationally complex and time-consuming especially with the limited computing capability of the on-board computer,posing challenges for practical engineering applications.To conquer these difficulties,this paper makes the following key contributions:(A)a turn-based(sequential decision-making)limited-area impulsive collision avoidance model considering the time delay of precision orbit determination is established for the first time;(B)a novel Selection Probability Learning Adaptive Search-depth Search Tree(SPL-ASST)algorithm is proposed for non-cooperative target avoidance,which improves the decision-making efficiency by introducing an adaptive-search-depth mechanism and a neural network into the traditional Monte Carlo Tree Search(MCTS).Numerical simulations confirm the effectiveness and efficiency of the proposed method.
基金supported by the National Natural Science Foundation of China(Nos.62103052 and No.52175214)。
文摘This paper presents the design of an asymmetrically variable wingtip anhedral angles morphing aircraft,inspired by biomimetic mechanisms,to enhance lateral maneuver capability.Firstly,we establish a lateral dynamic model considering additional forces and moments resulting during the morphing process,and convert it into a Multiple Input Multiple Output(MIMO)virtual control system by importing virtual inputs.Secondly,a classical dynamics inversion controller is designed for the outer-loop system.A new Global Fast Terminal Incremental Sliding Mode Controller(NDO-GFTISMC)is proposed for the inner-loop system,in which an adaptive law is implemented to weaken control surface chattering,and a Nonlinear Disturbance Observer(NDO)is integrated to compensate for unknown disturbances.The whole control system is proven semiglobally uniformly ultimately bounded based on the multi-Lyapunov function method.Furthermore,we consider tracking errors and self-characteristics of actuators,a quadratic programmingbased dynamic control allocation law is designed,which allocates virtual control inputs to the asymmetrically deformed wingtip and rudder.Actuator dynamic models are incorporated to ensure physical realizability of designed allocation law.Finally,comparative experimental results validate the effectiveness of the designed control system and control allocation law.The NDO-GFTISMC features faster convergence,stronger robustness,and 81.25%and 75.0%reduction in maximum state tracking error under uncertainty compared to the Incremental Nonlinear Dynamic Inversion Controller based on NDO(NDO-INDI)and Incremental Sliding Mode Controller based on NDO(NDO-ISMC),respectively.The design of the morphing aircraft significantly enhances lateral maneuver capability,maintaining a substantial control margin during lateral maneuvering,reducing the burden of the rudder surface,and effectively solving the actuator saturation problem of traditional aircraft during lateral maneuvering.
基金supported by the National Natural Science Foundation of China(Grant Nos.61375102, 61333016 and 61421004)
文摘In this paper,we present an overview of the mechanical design and control of biomimetic robotic fishes with high maneuverability.The robotic fishes modelled after Esoxlucius adopt multilink propulsive mechanism for a high turning rate and a small turning radius.According to different tasks,these robotic fishes are designed with decorated pectoral fins for a two-dimensional horizon plane,or controllable pectoral fins with multiple degrees of freedom for a three-dimensional space.Through observing and analyzing the fast-starts of real fish,we separately develop a dynamic trajectory tracking strategy based C-start control method and an L-shaped sliding method based S-start control method.Finally,a four-link robotic fish is able to execute C-start flexibly with a turning angle of up to 213°,a top turning rate of approximately670°/s,and an upper limit of turning precision of less than 10°and an S-start with a peak turning rate up to318.08±9.20°/s.The experimental results verify the feasibility of our high-maneuverability-oriented mechatronic design and control methods.
基金supported by the European Union by the Next Generation EU Project ECS00000017‘Ecosistema dell’Innovazione’Tuscany Health Ecosystem(THE,PNRR,Spoke 9:Robotics and Automation for Health)by the Italian Ministry of Education and Research(MUR)in the framework of the FoReLab project(Departments of Excellence).
文摘Muscle Shortening Maneuver(MSM)is a rehabilitation technique successfully applied to several pathological conditions.The concept is to passively elongate and shorten the target muscle group of the affected limb.As a result,the functionality(muscle strength and range of motion)of that limb is improved.The existing system induces these oscillations manually or without any feedback control,which can compromise the effectiveness and standardization of MSM.In this paper,we present a mechatronic system that can precisely deliver motion oscillations to the upper limb for a controllable execution of MSM.First,we collected the parameters(frequency and amplitude of the oscillations)from a system where a motor was heuristically used by a well-experienced therapist to induce the oscillations(without any feedback control).Based on these specifications,we chose the motor and rebuilt the experimental setup,implementing a sliding mode control with a sliding perturbation observer.With our system,the operator can choose a given frequency and amplitude of the oscillations within the range we experimentally observed.We tested our system with ten participants of different anthropometry.We found that our system can accurately reproduce oscillations in the frequency range 0.8 to 1.2 Hz and amplitude range 2 to 6 cm,with a maximum percentage normalized root mean square error around 7%.
文摘1) Introduction: Ventilation disorders of the middle ear play a major role in everyday clinical ENT-practice and sometimes represent a major therapeutic challenge. In addition to the conventional therapy of tympanostomy tube insertion, tuboplasty (TP) offers a less invasive option for treating this problem. The study should examine whether TP can be performed in a rural setting. 2) Material and methods: This is a prospective, monocentric study of patients scheduled for TP because of tubal ventilation disorder (TVD) in a rural region of Germany. The diagnosis was established after a thorough clinical examination and by assessing the possibility of performing the Valsalva maneuver, the tympanogram type, recording the middle ear pressure and air-bone gap. The subjective impairment caused by the TVD was evaluated using the EDTQ-7 questionnaire pre- and approximately 3 months postoperatively. 3) Results: Sixty-two patients with 92 TP were included with a mean age of 44.1 years. The EDTQ-7 score decreased highly significantly from 3.6 to 1.7 (p < 0.0001) without correlating with parameters such as age, sex, BMI, allergies or smoking. Middle ear pressure fell in average by −87 daPa, resulting in an improvement of the tympanogram type. The preoperative air-bone gap of 10.2 dB also was reduced significantly in most patients to 8.0 dB after the procedure. No notable complications occurred beside a sore throat due to the use of a laryngeal mask for ventilation during anesthesia in two cases. 4) Conclusion: In our experience, TP represents a less invasive and, in many cases, successful alternative to the established tympanostomy tube insertion with the advantage of an intact eardrum. It can also be offered and successfully performed in a rural setting.
基金supported by the National Natural Science Foundation of China(Nos.12372052,12125207)the Young Elite Scientists Sponsorship Program,China(No.2021JCJQ-QT-047)+1 种基金the Natural Science Foundation of Hunan Province,China(No.2023JJ20047)the Technology Innovation Team of Manned Space Engineering,China。
文摘The concept of the spacecraft Reachable Domain(RD)has garnered significant scholarly attention due to its crucial role in space situational awareness and on-orbit service applications.While the existing research has largely focused on single-impulse RD analysis,the challenge of Multi-Impulse RD(MIRD)remains a key area of interest.This study introduces a methodology for the precise calculation of spacecraft MIRD.The reachability constraints specific to MIRD are first formulated through coordinate transformations.Two restricted maneuvering strategies are examined.The derivation of two extremum conditions allows for determining the accessible orientation range and the nodes encompassing the MIRD.Subsequently,four nonlinear programming models are developed to address two types of MIRD by skillfully relaxing constraints using scale factors.Numerical results validate the robustness and effectiveness of the proposed approach,showing substantial agreement with Monte Carlo simulations and confirming its applicability to spacecraft on various elliptical orbits.
文摘1 The grandfather was choking on a mouthful of food,unable to breathe and unable to cough.The grandson,recalling the important lesson learned during the 8-13 Project organized by the Italian Red Cross⁃Poggi⁃Sermide Committee,suggested performing the Heimlich manoeuvre(海姆立克急救法)on the elderly man.
基金Natural Science Foundation of Heilongjiang Province of China(Grant No.YQ2022F012)the Fundamental Research Funds for the Central Universities(Grant No.HIT.OCEF.2023010)to provide fund for conducting experiments.
文摘Aiming at the missile avoidance problem of the unmanned aerial vehicle(UAV)in complex obstacle environments,this work proposes a collision-avoidance method based on receding horizon optimization.The proposed method generated a specific trajectory for the UAV to effectively induce the proportional navigation missile to successfully intercept the obstacle,thereby accomplishing the evasive maneuver.The evasive maneuver was divided into two distinct stages,namely the collision-inducing phase and the fast departure phase.The obstacle potential field-based target selection algorithm was employed to identify the most appropriate target obstacle,while the induced trajectory was determined through a combination of receding horizon optimization and the hp-adaptive pseudo-spectral method.Simulation experiments were carried out under three different types of obstacle environments and one multiobstacle environment,and the simulation results show that the method proposed in this paper greatly improves the success rate of UAV evasive maneuvers,proving the effectiveness of this method.
基金Sponsored by National Natural Science Foundation of China(Grant No.61973326)Shenzhen Science and Technology Program(Grant No.ZDSYS20210623091808026)Key Laboratory of Cross-Domain Flight Interdisciplinary Technology(Grant No.2024-KF02201).
文摘In order to enhance the penetration performance of hypersonic gliding vehicle,a chaotification method of gliding midcourse based on flight dynamics is proposed.Firstly,a chaotic series⁃based angle of attack(AOA)control algorithm and an AOA switching control algorithm considering flight altitude are proposed in this study based on a simple chaotic system with considerations of AOA constraints and process constraints.Secondly,the Lyapunov exponent Algorithm Of Continuous system is applied to verify the chaotic characteristic of flight trajectories.Thirdly,a stability region analysis method is proposed based on a conservative dynamics,which can be applied to the stability region analysis of general complex dynamics.Finally,the simulations show that both control algorithms can realize the chaotification of trajectories,and the flight trajectories obtained by the AOA switching control algorithm are feasible.
基金supported by Natural Science Basic Research Plan in Shaanxi Province of China(No.2023-JC-QN-0733)Guangdong Basic and Applied Basic Research Foundation,China(No.2022A1515110753)+2 种基金China Postdoctoral Science Foundation(No.2022M722583)China Industry-UniversityResearch Innovation Foundation(No.2022IT188)National Key Laboratory of Air-based Information Perception and Fusion and the Aeronautic Science Foundation of China(No.20220001068001)。
文摘The paper presents a two-layer,disturbance-resistant,and fault-tolerant affine formation maneuver control scheme that accomplishes the surrounding of a dynamic target with multiple underactuated Quadrotor Unmanned Aerial Vehicles(QUAVs).This scheme mainly consists of predefinedtime estimators and fixed-time tracking controllers,with a hybrid Laplacian matrix describing the communication among these QUAVs.At the first layer,we devise predefined time estimators for leading and following QUAVs,enabling accurate estimation of desired information.In the second layer,we initially devise a fixed-time hybrid observer to estimate unknown disturbances and actuator faults.Fixedtime translational tracking controllers are then proposed,and the intermediary control input from these controllers is used to extract the desired attitude and angular velocities for the fixed-time rotational tracking controllers.We employ an exact tracking differentiator to handle variables that are challenging to differentiate directly.The paper includes a demonstration of the control system stability through mathematical proof,as well as the presentation of simulation results and comparative simulations.
基金supported by National Key R&D Program of China:Gravitational Wave Detection Project(Grant Nos.2021YFC22026,2021YFC2202601,2021YFC2202603)National Natural Science Foundation of China(Grant Nos.12172288 and 12472046)。
文摘This paper investigates impulsive orbital attack-defense(AD)games under multiple constraints and victory conditions,involving three spacecraft:attacker,target,and defender.In the AD scenario,the attacker aims to breach the defender's interception to rendezvous with the target,while the defender seeks to protect the target by blocking or actively pursuing the attacker.Four different maneuvering constraints and five potential game outcomes are incorporated to more accurately model AD game problems and increase complexity,thereby reducing the effectiveness of traditional methods such as differential games and game-tree searches.To address these challenges,this study proposes a multiagent deep reinforcement learning solution with variable reward functions.Two attack strategies,Direct attack(DA)and Bypass attack(BA),are developed for the attacker,each focusing on different mission priorities.Similarly,two defense strategies,Direct interdiction(DI)and Collinear interdiction(CI),are designed for the defender,each optimizing specific defensive actions through tailored reward functions.Each reward function incorporates both process rewards(e.g.,distance and angle)and outcome rewards,derived from physical principles and validated via geometric analysis.Extensive simulations of four strategy confrontations demonstrate average defensive success rates of 75%for DI vs.DA,40%for DI vs.BA,80%for CI vs.DA,and 70%for CI vs.BA.Results indicate that CI outperforms DI for defenders,while BA outperforms DA for attackers.Moreover,defenders achieve their objectives more effectively under identical maneuvering capabilities.Trajectory evolution analyses further illustrate the effectiveness of the proposed variable reward function-driven strategies.These strategies and analyses offer valuable guidance for practical orbital defense scenarios and lay a foundation for future multi-agent game research.
