The investigation on flight quality of tilt-rotor aircraft

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ke Lu ◽  
Shanyong Zhao ◽  
YUjie Ma ◽  
Shangjing Wu ◽  
Cheng da Su
Keyword(s):  
Tracking Control ◽  
Control Method ◽  
Quantitative Relationship ◽  
Explicit Model ◽  
Content Type ◽  
Tilt Rotor ◽  
Motion Modes ◽  
Aerodynamic Derivatives ◽  
Quality Specifications

Purpose This paper aims to present an investigation on flight quality analysis and design of tilt-rotor aircraft combined with corresponding flight quality specifications. Design/methodology/approach From the perspective of modal characteristics of tilt-rotor aircraft, it focuses on the analysis of the change rules of the longitudinal short-term motion mode, lateral roll convergence mode, spiral mode and Dutch roll mode. Then, the flight quality design research is carried out using the explicit model tracking control method. The quantitative relationship between flight quality requirements and explicit model is established. Accordingly, the closed-loop flight quality of XV-15 tilt-rotor aircraft is evaluated. Findings The stability of spiral mode is the result of the interaction of various aerodynamic derivatives and spiral instability occurs in helicopter mode. The other motion modes are stable in full flight mode and meet the requirements of level 1 specified in ADS-33E-PRF and MIL-F-8785C flight quality specifications. There is a quantitative relationship between flight quality requirements and explicit model, and the flight quality of tilt-rotor aircraft is improved through the explicit model tracking control method. Practical implications The presented analysis results showed the influence of motion modes and flight quality and the effectiveness of explicit model tracking control method in flight quality improvement, which could be considered as new information for further flight quality design of tilt-rotor aircraft. Originality/value The originality of the paper lies in the proposed design and analysis method of the flight quality of tilt-rotor aircraft from the direction of the influence of its aerodynamic derivatives and motion modes.

Dynamic trajectory-tracking control method of robotic transcranial magnetic stimulation with end-effector gravity compensation based on force sensors

2018 ◽  
Vol 45 (6) ◽  
pp. 722-731
Author(s):  
ZeCai Lin ◽  
Wang Xin ◽  
Jian Yang ◽  
Zhang QingPei ◽  
Lu ZongJie
Keyword(s):  
Neural Networks ◽  
Trajectory Tracking ◽  
Tracking Control ◽  
Magnetic Stimulation ◽  
Control Method ◽  
Gravity Compensation ◽  
Trajectory Tracking Control ◽  
End Effector ◽  
Content Type ◽  
Dynamic Trajectory

Purpose This paper aims to propose a dynamic trajectory-tracking control method for robotic transcranial magnetic stimulation (TMS), based on force sensors, which follows the dynamic movement of the patient’s head during treatment. Design/methodology/approach First, end-effector gravity compensation methods based on kinematics and back-propagation (BP) neural networks are presented and compared. Second, a dynamic trajectory-tracking method is tested using force/position hybrid control. Finally, an adaptive proportional-derivative (PD) controller is adopted to make pose corrections. All the methods are designed for robotic TMS systems. Findings The gravity compensation method, based on BP neural networks for end-effectors, is proposed due to the different zero drifts in different sensors’ postures, modeling errors in the kinematics and the effects of other uncertain factors on the accuracy of gravity compensation. Results indicate that accuracy is improved using this method and the computing load is significantly reduced. The pose correction of the robotic manipulator can be achieved using an adaptive PD hybrid force/position controller. Originality/value A BP neural network-based gravity compensation method is developed and compared with traditional kinematic methods. The adaptive PD control strategy is designed to make the necessary pose corrections more effectively. The proposed methods are verified on a robotic TMS system. Experimental results indicate that the system is effective and flexible for the dynamic trajectory-tracking control of manipulator applications.

Influences of airfoil profile on lateral-directional stability of aircraft with flying wing layout

2019 ◽  
Vol 91 (7) ◽  
pp. 1011-1017 ◽  
Author(s):  
Yalin Pan ◽  
Jun Huang
Keyword(s):  
Flight Control ◽  
Critical Factor ◽  
Parametric Modeling ◽  
Quality Level ◽  
Lattice Method ◽  
Content Type ◽  
Directional Stability ◽  
Aerodynamic Derivatives ◽  
Dutch Roll

Purpose The purpose of this study is to analyze influence of airfoil profile on lateral-directional flying quality of flying wing aircraft. The lateral-directional stability is always insufficient for aircraft with the layout due to the absence of vertical stabilizer. A flying wing aircraft with double-swept wing is used as research object in the paper. Design/methodology/approach The 3D model is established for the aircraft with flying wing layout, and parametric modeling is carried out for airfoil mean camber line of the aircraft to analyze lateral-directional stability of the aircraft with different camber line parameters. To increase computational efficiency, vortex lattice method is adopted to calculate aerodynamic coefficients and aerodynamic derivatives of the aircraft. Findings It is found from the research results that roll mode and spiral mode have a little effect on lateral-directional stability of the aircraft but Dutch roll mode is the critical factor affecting flying quality level of such aircraft. Even though changes of airfoil mean line parameters can greatly change assessment parameters of aircraft lateral-directional flying quality, that is kind of change cannot have a fundamental impact on level of flying quality of the aircraft. In case flat shape parameters are determined, the airfoil profile has a limited impact on Dutch roll mode. Originality/value Influences of airfoil profile on lateral-directional flying quality of aircraft with double-swept flying wing layout are revealed in the thesis and some important rules and characteristics are also summarized to lay a theoretical basis for design of airfoil and flight control system of aircraft with the layout.

Control method of spray curing system for cement concrete members based on the AdaBoost.M1 algorithm

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wei Yuan ◽  
Renfeng Yang ◽  
Jianyou Yu ◽  
Qunrong Zeng ◽  
Zechen Yao
Keyword(s):  
Machine Learning ◽  
Control Method ◽  
Current Control ◽  
Machine Learning Algorithms ◽  
Classification Model ◽  
Critical Parameters ◽  
Cement Concrete ◽  
Content Type ◽  
Concrete Members

Purpose Spray curing has become the preferred curing method for most cement concrete members because of its lower cost and sound effect. However, the spray curing quality of members is vulnerable to random variation environment factors and anthropogenic interferences. This paper aims to introduce the machine learning algorithm into the spray curing system to optimize its control method to improve the spray curing quality of members. Design/methodology/approach The critical parameters affecting the spray curing quality of members were collected through experiments, such as the temperature and humidity of the member's surface, the temperature, humidity and wind speed of the environment. The C4.5 algorithm was used as a weak classifier algorithm, and the AdaBoost.M1 algorithm was used to cascade multiple weak classifiers to form a robust classifier according to the collected data. Findings The results showed that the model constructed by the AdaBoost.M1 algorithm had achieved higher accuracy and robustness among the two algorithms. Based on the classification model built by the AdaBoost.M1 algorithm, the spray curing system can cause automatic decision-making spray switching according to the member's real-time curing state and environment. Originality/value With the classification model constructed by the AdaBoost.M1 algorithm, the spray curing system can overcome the disadvantages that external factors greatly influence the current control method of the spray curing system, and the intelligent control of the spray curing system was realized to a certain extent. This paper provides a reference for applying machine learning algorithms in the intellectual transformation of bridge construction equipment.

An Application of Unified Power Quality Conditioner for Micro-Grid

2013 ◽  
Vol 380-384 ◽  
pp. 3149-3154
Author(s):  
Han Guo Yu ◽  
Jian Ru Wan ◽  
Ran Liu
Keyword(s):  
Power Quality ◽  
Tracking Control ◽  
Control Method ◽  
Control Program ◽  
Nonlinear Load ◽  
Unified Power Quality Conditioner ◽  
New Energy ◽  
Micro Grid ◽  
Power Quality Conditioner

According to the power quality problems of micro-grid, this paper presents a control program of the Unified Power Quality Conditioner (UPQC) to improve the micro-grid power quality.The shunt side of UPQC is used to eliminate the harmonic current brought by nonlinear load into the micro-grid. And the conditioner series part is used to suppress distributed new energy generation intermittence. In the paper synchronous coordinate transformation is used to detect compensated components and tracking control method is adopted to control the converter. The simulation results demonstrate the effectiveness of the UPQC on improving the power quality of the micro-grid.

A Fuzzy Self-Learning Control Method with Application to Hydroforming Processes

1995 ◽  
Vol 117 (3) ◽  
pp. 297-303 ◽  
Author(s):  
H. J. Park ◽  
H. S. Cho
Keyword(s):  
Tracking Control ◽  
Control Method ◽  
Learning Control ◽  
Design Parameters ◽  
High Quality ◽  
Control Scheme ◽  
Series Of Experiments ◽  
Quality Of Products ◽  
Self Learning

In this paper, a tracking control of hydroforming pressure which is used for precision forming of sheet metals, is considered. In this process, forming pressure of the process needs to be strictly controlled to ensure high quality of the forming products. However, conventional control method alone makes it difficult to achieve satisfactory control performance due to complexities and uncertainties of the process. To overcome this problem, a fuzzy self-learning control scheme is proposed. In the proposed scheme, a series of experiments were performed to show the effectiveness of the proposed control scheme and to investigate influence of the design parameters of the proposed algorithm. The experimental results show that the proposed fuzzy self-learning controller can guarantee good tracking performance and thus, high quality of products even when knowledge of the process is vague, imprecise and fragmentary.

A hybrid controller for PWM active rectifiers based LCL filters

2015 ◽  
Vol 34 (4) ◽  
pp. 1229-1251 ◽  
Author(s):  
Amira Marzouki ◽  
Mahmoud Hamouda ◽  
Farhat Fnaiech
Keyword(s):  
Control Method ◽  
Hybrid Control ◽  
High Quality ◽  
Lcl Filter ◽  
Content Type ◽  
Linear Controller ◽  
Dc Bus ◽  
Bus Voltage ◽  
Active Rectifiers

Purpose – The purpose of this paper is to propose a new hybrid control method of pulse width modulation (PWM) active rectifiers tied to the grid through an LCL filter. The control method is designed with the aim to achieve a perfect regulation of the dc-bus voltage; a near unity input power factor (UIPF) operation as well as a high quality of the line currents. Design/methodology/approach – The proposed hybrid control method consists of a PI-based linear controller cascaded with a nonlinear one. The nonlinear controller (inner loop) is designed using the input-output feedback linearization (IOFL) theory. It should control both the dc-bus voltage and the input currents at the converter’s poles. The linear controller (outer loop) is devoted to control the reactive line current so as to achieve a near UIPF. Findings – A perfect regulation of the dc-bus voltage and a near UIPF operation are achieved. Moreover, a high quality of the line currents is obtained. The robustness and effectiveness of the proposed control method have been successfully tested under variation of the dc voltage reference as well as grid and load disturbances. Practical implications – The proposed method is useful for single-stage and two-stage grid connected photovoltaic systems, wind energy conversion, and distributed power generation systems. Originality/value – The main novelty of this paper is the combination of linear and nonlinear controllers with the aim to control a PWM active rectifier tied to the grid through a third-order LCL filter. In the opinion, such control method has not been applied to this converter in earlier research papers. The numerical simulations carried out under normal and abnormal conditions confirm the effectiveness of the proposed approach.

Design and performance analysis of an industrial robot arm for robotic drilling process

2019 ◽  
Vol 46 (1) ◽  
pp. 7-16 ◽  
Author(s):  
Longfei Sun ◽  
Fengyong Liang ◽  
Lijin Fang
Keyword(s):  
Control Method ◽  
Industrial Robot ◽  
Industrial Robots ◽  
Ball Screw ◽  
Robotic Arm ◽  
Drilling Process ◽  
Robot Arm ◽  
Content Type ◽  
Robotic Drilling

Purpose The purpose of this paper is to present a robotic arm that can offer better stiffness than traditional industrial robots for improving the quality of holes in robotic drilling process. Design/methodology/approach The paper introduces a five-degree of freedom (DOF) robot, which consists of a waist, a big arm, a small arm and a wrist. The robotic wrist is composed of two DOFs of pitching and tilting. A parallelogram frame is used for robotic arms, and the arm is driven by a linear electric cylinder in the diagonal direction. Double screw nuts with preload are used in the ball screw to remove the reverse backlash. In addition, dual-motor drive is applied for each DOF in the waist and the wrist to apply anti-backlash control method for eliminating gear backlash. Findings The proposed robotic arm has the potential for improving robot stiffness because of its truss structure. The robot can offer better stiffness than industrial robots, which is beneficial to improve the quality of robotic drilling holes. Originality/value This paper includes the design of a five-DOF robot for robotic drilling tasks, and the stiffness modeling of the robot is presented and verified by the experiment. The robotic system can be used instead of traditional industrial robots for improving the hole quality to a certain extent.

Trajectory tracking control of robotic transcranial magnetic stimulation

2019 ◽  
Vol 12 (2) ◽  
pp. 245-259 ◽  
Author(s):  
Zecai Lin ◽  
Xin Wang ◽  
Jian Yang
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Augmented Reality ◽  
Trajectory Tracking ◽  
Force Control ◽  
Tracking Control ◽  
Magnetic Stimulation ◽  
Control Method ◽  
Trajectory Tracking Control ◽  
Content Type ◽  
Augmented Reality Technology

Purpose Transcranial magnetic stimulation (TMS) is a non-invasive brain stimulation technique. Based on the unique functions of TMS, it has been widely used in clinical, scientific research and other fields. Nowadays, the robot-assisted automatic TMS has become the trend. In order to simplify the operation procedures of robotic TMS and reduce the costs, the purpose of this paper is to apply the marker-based augmented-reality technology to robotic TMS system. Design/methodology/approach By using the marker of ARToolKitPlus library and monocular camera, the patient’s head is positioned in real time. Furthermore, the force control is applied to keep contact between the coil and subject’s head. Findings The authors fuse with visual positioning which is based on augmented-reality and force-control technologies to track the movements of the patient’s head, bring the coil closer to the stimulation site and increase treatment effects. Experimental results indicate that the trajectory tracking control of robotic TMS system designed in this paper is practical and flexible. Originality/value This paper provides a trajectory tracking control method for the robotic TMS. The marker-based augmented-reality technology is implemented which simplifies the operation procedures of robotic TMS as well as reduce the costs. During the treatment process, the patients would wear an AR glasses, which can help patients relax through virtual scenes and reduce the uncomfortableness produce by treatment.

METHODS ASSESSMENT QUALITY OF ACCOUNTING REPORTING AND MODELS OF THEIR MEASUREMENT

2020 ◽  
Vol 3 (3) ◽  
pp. 95-99
Author(s):  
E. H. ABU ◽  
Keyword(s):  
Internal Control ◽  
Stock Prices ◽  
Control Method ◽  
Financial Statements ◽  
Accounting Conservatism ◽  
Standardized Assessment ◽  
Accrual Quality ◽  
Indirect Measures

The article explores individual approaches used to measure and evaluate the quality of financial state-ments: standardized assessment, accrual-based models (accrual quality), Beneise models (M-Score), in-dexes - the internal control method and the degree of accounting conservatism. The reason for the great dependence on the use of indirect measures (proxies for the quality of financial statements or stock prices) is that some of the qualities of financial statements are unobservable.

Quality Improvement of the DNA extracted by boiling method in Gram negative bacteria

2017 ◽  
Vol 6 (04) ◽  
pp. 5347 ◽  
Author(s):  
Omar B. Ahmed* ◽  
Anas S. Dablool
Keyword(s):  
Dna Extraction ◽  
Control Method ◽  
Extraction Procedure ◽  
Cost Effective ◽  
High Yield ◽  
Gram Negative Bacteria ◽  
Bacterial Dna ◽  
Gram Negative ◽  
E Coli

Several methods of Deoxyribonucleic acid (DNA) extraction have been applied to extract bacterial DNA. The amount and the quality of the DNA obtained for each one of those methods are variable. The study aimed to evaluate bacterial DNA extraction using conventional boiling method followed by alcohol precipitation. DNA extraction from Gram negative bacilli was extracted and precipitated using boiling method with further precipitation by ethanol. The extraction procedure performed using the boiling method resulted in high DNA yields for both E. coli and K. pneumoniae bacteria in (199.7 and 285.7μg/ml, respectively) which was close to control method (229.3 and 440.3μg/ml). It was concluded that after alcohol precipitation boiling procedure was easy, cost-effective, and applicable for high-yield quality of DNA in Gram-negative bacteria.

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