Modeling and control for ultra-low altitude cargo airdrop

2018 ◽  
Vol 90 (1) ◽  
pp. 219-228
Author(s):  
Yanhua Han
Keyword(s):  
Numerical Simulation ◽  
Flight Control ◽  
Control Law ◽  
Dynamics Model ◽  
Aerodynamic Coefficients ◽  
Content Type ◽  
Coupling Dynamics ◽  
Low Altitude ◽  
And Control ◽  
Kane Method

Purpose The purpose of this paper is to model the aircraft-cargo’s coupling dynamics during ultra-low altitude heavy cargo airdrop and to design the aircraft’s robust flight control law counteracting its aerodynamic coefficients perturbation induced by ground effect and the disturbance from the sliding cargo inside. Design/methodology/approach Aircraft-cargo system coupling dynamics model in vertical plane is derived using the Kane method. Trimmed point is calculated when the cargo fixed in the cabin and then the approximate linearized motion equation of the aircraft upon it is derived. The robust stability and robust H∞ optimal disturbance restraint flight control law are designed countering the aircraft’s aerodynamic coefficients perturbation and the disturbance moment, respectively. Findings Numerical simulation shows the effectiveness of the proposed control law with elevator deflection as a unique control input. Practical implications The model derived and control law designed in the paper can be applied to heavy cargo airdrop integrated design and relevant parameters choice. Originality/value The dynamics model derived is closed, namely, the model can be called in numerical simulation free of assuming the values of parachute’s extraction force or cargo’s relative sliding acceleration or velocity as seen in many literatures. The modeling is simplified using Kane method rather than Newton’s laws. The robust control law proposed is effective in guaranteeing the aircraft’s flight stability and disturbance restraint performance in the presence of aerodynamic coefficients perturbation.

Simulation and measurement study of metro wheel wear based on the Archard model

2019 ◽  
Vol 71 (2) ◽  
pp. 284-294 ◽  
Author(s):  
AiHua Zhu ◽  
Si Yang ◽  
Qiang Li ◽  
JianWei Yang ◽  
Xi Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Measured Data ◽  
Sequence Type ◽  
Dynamics Model ◽  
Wheel Wear ◽  
Matlab Software ◽  
Hertz Theory ◽  
Content Type ◽  
Vehicle Load ◽  
Wheel Profile

PurposeThe purpose of this paper is to study the wear evolution of metro wheels under the conditions of different track sequences, track composition and vehicle load and then to predict wheel wear and to guide its maintenance.MethodologyBy using the SIMPACK and MATLAB software, numerical simulation analysis of metro wheel wear is carried out based on Hertz theory, the FASTSIM algorithm and the Archard model. First of all, the vehicle dynamics model is established to calculate the motion relationship and external forces of wheel-rail in the SIMPACK software. Then, the normal force of wheel-rail is solved based on Hertz theory, and the tangential force of wheel-rail is calculated based on the FASTSIM algorithm through the MATLAB software. Next, in the MATLAB software, the wheel wear is calculated based on the Archard model, and a new wheel profile is obtained. Finally, the new wheel profile is re-input into the vehicle system dynamics model in the SIMPACK software to carry out cyclic calculation of wear.FindingsThe results show that the setting order of different curves has an obvious influence on wear when the proportion of the straight track and the curve is fixed. With the increase in running mileage, the severe wear zone is shifted from tread to flange root under the condition of the sequence-type track, but the wheel wear distribution is basically stable for the unit-type track, and their wear growth rates become closer. In the tracks with different straight-curved ratio, the more proportion the curved tracks occupy, the closer the severe wear zone is shifted to flange root. At the same time, an increase in weight of the vehicle load will aggravate the wheel wear, but it will not change the distribution of wheel wear. Compared with the measured data of one city B type metro in China, the numerical simulation results of wheel wear are nearly the same with the measured data.Practical implicationsThese results will be helpful for metro tracks planning and can predict the trend of wheel wear, which has significant importance for the vehicle to do the repair operation. At the same time, the security risks of the vehicle are decreased economically and effectively.Originality/valueAt present, many scholars have studied the influence of metro tracks on wheel wear, but mainly focused on a straight line or a certain radius curve and neglected the influence of track sequence and track composition. This study is the first to examine the influence of track sequence on metro wheel wear by comparing the sequence-type track and unit-type track. The results show that the track sequence has a great influence on the wear distribution. At the same time, the influence of track composition on wheel wear is studied by comparing different straight-curve ratio tracks; therefore, wheel wear can be predicted integrally under different track conditions.

scholarly journals Longitudinal flight control design with handling quality requirements

2006 ◽  
Vol 110 (1111) ◽  
pp. 627-637 ◽  
Author(s):  
D. Saussié ◽  
L. Saydy ◽  
O. Akhrif
Keyword(s):  
Flight Control ◽  
Control Law ◽  
Longitudinal Motion ◽  
Model Order ◽  
Quality Requirements ◽  
Loop Design ◽  
Business Jet ◽  
Stability Augmentation ◽  
Handling Quality ◽  
And Control

Abstract This work presents a method for selecting the gain parameters of a C* control law for an aircraft’s longitudinal motion. The design incorporates various handling quality requirements involving modal, time- and frequency-domain criteria that were fixed by the aircraft manufacturer. After necessary model order-reductions, the design proceeds in essentially two-steps: stability augmentation system (SAS) loop design and control augmentation system (CAS) loop design. The approach partly relies on the use of guardian maps to characterise, in each case, the set of gain parameters for which desired handling quality requirements are satisfied. The approach is applied throughout the full flight envelope of a business jet aircraft and yields satisfactory results.

Multi-Mode Flight Control Simulation of UAV Based on Stateflow and GUI

2012 ◽  
Vol 241-244 ◽  
pp. 1545-1549
Author(s):  
Ning Zhang ◽  
Hua Wei Chen ◽  
Kai Yu Qin
Keyword(s):  
Remote Control ◽  
Simulation Model ◽  
Flight Control ◽  
Control Law ◽  
Control Logic ◽  
Control Instruction ◽  
And Control ◽  
Designing Method ◽  
Multi Mode ◽  
Navigation Strategies

Considering a UAV has different flight control modes, such as remote control instruction flight and auto-navigation flight, this paper uses modular designing method to describe the overall structure of simulation model, and based on the way of loading waypoint, focuses on discussing the control logic of auto-navigation flight. Furthermore, according to the flight control logic of UAV, the simulation model was built by using Stateflow, and combining with Matlab GUI, the remote control instruction was realized. The simulation results in the auto-navigation flight can effectually verify the correctness of the design of flight navigation strategies and control law. It is practical to build the simulation environment by using Stateflow and GUI technology.

Flight controller design for aircraft low altitude airdrop

2016 ◽  
Vol 88 (6) ◽  
pp. 689-696 ◽  
Author(s):  
Ri Liu ◽  
Xiuxia Sun ◽  
Wenhan Dong
Keyword(s):  
Flight Control ◽  
Feedback Linearization ◽  
Control Method ◽  
Controller Design ◽  
Sliding Mode ◽  
Integral Term ◽  
Content Type ◽  
Integral Sliding Mode ◽  
Sliding Manifold ◽  
Low Altitude

Purpose During low altitude airdrop operations, the heavy cargo moving inside and the sudden dropping out exert serious threats on the aircraft safety and mission performance. This paper aims to propose an efficient flight control method for the airdrop operations. Design/methodology/approach A novel controller which combines feedback linearization with nonlinear integral sliding mode control is proposed. The aircraft airdrop model is decoupled and linearized by using the feedback linearization technique. On this basis, an integral sliding mode controller is designed to stabilize the speed and pitch attitude of the aircraft. In the sliding manifold, one class of nonlinear functions with the property of “smaller errors correspond to bigger gains and bigger errors correspond to saturated gains” is introduced to form the integral term; thus, the overcompensation of the integral term to big errors is omitted, and the dynamic response performance is improved. Lyapunov-based stability analysis shows that the controller could completely reject model uncertainties by choosing proper controller parameters. Findings The flight control system with strong robustness could meet the low altitude airdrop indexes in the maximum weight cargo airdrop task. Originality/value This paper fulfils an urgent need to study how to control the aircraft to guarantee mission performance and flight safety during the low altitude airdrop operations.

Aircraft flight characteristics in conditions of windshear and icing

2007 ◽  
Vol 111 (1115) ◽  
pp. 41-49 ◽  
Author(s):  
Yihua Cao ◽  
Kungang Yuan
Keyword(s):  
Flight Control ◽  
Inverse Dynamics ◽  
Weather Conditions ◽  
Ice Accretion ◽  
Control Logic ◽  
Stability And Control ◽  
Aircraft Flight ◽  
Low Altitude ◽  
Flight Dynamics Model ◽  
And Control

Abstract Complex weather conditions, especially windshear and icing encounter, have severe effects on aircraft flight safety. The effect of low-altitude windshear and ice accretion on aircraft performance and control has been studied in this paper. With the employment of a windshear model and nonlinear inverse dynamics (NID) method, a low-altitude windshear penetration flight control law is designed. The effect of ice accretion was modeled on the stability and control of an aircraft. Several icing parameters are imported to the small disturbance flight dynamics model to calculate the change of performance, stability and control derivatives between clean and iced aircraft. These derivatives were used to calculate the elevator, the aileron and the rudder step responses to investigate the icing effect. The simulation results indicate that the NID control logic works effectively in the trajectory control of the aircraft during the penetration of windshear. The method used to study the effect of ice accretion on aircraft is valid and it can provide data for real-time calculation for icing encounter.

On Aero Control Law Joined Compensatory PID for Glide down to Fixed Low Altitude System and Simulation Researches

2012 ◽  
Vol 198-199 ◽  
pp. 1021-1024
Author(s):  
De Hai Yu ◽  
Dong Cai Qu ◽  
Jian Hua Lu ◽  
Bin Wen Lu
Keyword(s):  
Control Law ◽  
Simple Analysis ◽  
Control Laws ◽  
Control Scheme ◽  
Improve Accuracy ◽  
Working Principle ◽  
Simulation Results ◽  
Low Altitude ◽  
Constant Altitude ◽  
And Control

In order to improve accuracy of constant altitude fly at low altitude and fly track of glide down to fixed altitude, aeroplane’s control scheme of glide down to fixed low altitude with PID compensatory link were designed. At the same time, the corresponding control laws had been designed. After simple analysis about working principle of the aeroplane’s control system, simulation researches were done to optimize designed control laws, so that achieving expectant requirement. Simulation results show that designed control scheme and control law were accurate and effective.

Case Studies of System Identification Modeling for Flight Control Design

2013 ◽  
Vol 58 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Christina M. Ivler ◽  
Mark B. Tischler
Keyword(s):  
System Identification ◽  
Flight Control ◽  
Control Design ◽  
Flight Test ◽  
Unmanned Aircraft ◽  
Integrated System ◽  
Control Law ◽  
Dynamics Model ◽  
Identification Methods ◽  
Flight Dynamics Model

Flight control design and analysis requires an accurate flight dynamics model of the bare airframe and its associated uncertainties, as well as the integrated system model (block diagrams), across the frequency range of interest. Frequency response system identification methods have proven to efficiently fulfill these modeling requirements in recent rotorcraft flight control applications. This paper presents integrated system identification methods for control law design with flight-test examples of the Fire Scout MQ-8B, S-76, and ARH-70A. The paper also looks toward how system identification could be used in new modeling challenges such as large tilt-rotors and uniquely configured unmanned aircraft.

Minimum-Time Eigenaxis Rotation Maneuvers for a Spacecraft With Three Axis Reaction Wheels

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Haoyu Wang ◽  
Guowei Zhao ◽  
Hai Huang
Keyword(s):  
Numerical Simulation ◽  
Momentum Conservation ◽  
Open Loop ◽  
Minimum Time ◽  
Control Law ◽  
Open Loop Control ◽  
Model Uncertainties ◽  
Loop Control ◽  
Control Scheme ◽  
And Control

This paper proposes a planning method of the theoretically fastest slew path, and correspondingly, an analytical open-loop control law for the minimum-time eigenaxis rotation of spacecraft with three reaction wheels. The path planning and the control law are based on the angular momentum conservation of the spacecraft system. Then, a control scheme is also proposed to correct the maneuver error caused by model uncertainties. The control law and control scheme are verified in numerical simulation cases. The results show that the control law would realize the fastest slew path for an eigenaxis rotation, and the control scheme is feasible in shortening the slew time.

Principle and experimental research on vibration reduction of flexible solar array using reaction flywheel

2018 ◽  
Vol 90 (8) ◽  
pp. 1282-1287 ◽  
Author(s):  
Bifa Chen ◽  
Meiyan Zhang ◽  
Guo-an Tang
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Structural Damage ◽  
Vibration Suppression ◽  
Vibration Reduction ◽  
Experimental Studies ◽  
Scale Model ◽  
Solar Array ◽  
Control Law ◽  
Content Type

Purpose The rest-to-rest movements for the spacecraft, such as attitude adjustment and orbital maneuver, are likely to excite residual vibration of the flexible appendages, which may affect the attitude accuracy and even result in severe structural damage. This paper presents an approach to attenuating the vibration of flexible solar array by using reaction flywheel. Design/methodology/approach The reaction flywheel installed on solar array is served as an actuator to provide reaction torque to the structure according to the designed feedback control law. This torque can be considered as an artificial damping. Experiment on a scale model of the solar array is firstly performed to verify the effectiveness of this method. Numerical simulation on finite element model of a full-scale solar array is subsequently carried out to confirm the validity of this method for practical engineering application. Findings The vibration suppression effect on the structure by using reaction flywheel is deduced by theoretical analysis. Results from both experiment and numerical simulation reveal that the efficiency of vibration attenuation is promoted. Research limitations/implications Improvements on control law are left for further study. Additionally, only the first-order bending vibration of the flexible solar array is attenuated, and further study is required for other types of vibration suppression. Practical implications An effective method is proposed for spacecraft designers to actively suppress the vibration of the flexible solar array. Originality/value A novel active vibration reduction scheme is proposed by using reaction flywheel to suppress vibration of the flexible solar array. This paper fulfills a source of theoretical analysis and experimental studies for vibration reduction measure design and provides practical help for the spacecraft designers.

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