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Data-driven active vibration control for helicopter with trailing-edge flaps using adaptive dynamic programming

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Chinese Journal of Aeronautics 2024年第6期37卷 151-166页

作者： Yu CHEN Qun ZONG Xiuyun ZHANG Jinna LI School of Electrical and Information Engineering Tianjin UniversityTianjin 300072China School of Information and control Engineering Liaoning Petrochemical UniversityFushun 113001China

The helicopter Trailing-Edge Flaps(TEFs)technology is one of the recent hot topics in morphing wing *** employing controlled deflection,TEFs can effectively reduce the vibration level of ***,designing specific vibration reduction control methods for the helicopters equipped with trailing-edge flaps is of significant practical *** paper studies the optimal control problem for helicopter-vibration systems with TEFs under the framework of adaptive dynamic programming combined with Reinforcement Learning(RL).Time-delay and disturbances,caused by complexity of helicopter dynamics,inevitably deteriorate the control performance of vibration *** solve this problem,a zero-sum game formulation with a linear quadratic form for reducing vibration of helicopter systems is presented with a virtual *** this context,an off-policy reinforcement learning algorithm is developed to determine the optimal control *** algorithm utilizes only vertical vibration load data to achieve a policy that reduces vibration,attains Nash equilibrium,and addresses disturbances while compensating for time-delay without knowledge of the dynamics of the helicopter *** effectiveness of the proposed method is demonstrated in a virtual platform.

关键词： active control Adaptive dynamic program-ming Helicopter rotor Vibration control Zero-sum game

active control of turbulence for drag reduction based on the detection of near-wall streamwise vortices by wall information

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Acta Mechanica Sinica 2015年第4期31卷 512-522页

作者： Mingwei Ge Chunxiao Xu Gui-Xiang Cui School of Renewable Energy North China Electric Power University School of Aerospace Tsinghua University

The spatial relations between the measurable wall quantities （streamwise shear stress τwx, spanwise shear stress τwz, and pressure fluctuations Pw） and the near-wall streamwise vortices （NWSV） are investigated via direct numerical simulation （DNS） databases of fully developed turbulent channel flow at a low Reynolds number. In the stan- dard turbulent channel flow, the results show that all the wall measurable variables are closely associated with the NWSV. But after applying a stochastic interference, the relation based on τwx breaks down while the correlations based on Pw and τwz are still robust. Hence, two wall flow quantities based on Pw and τwz are proposed to detect the NWSV. As an appli- cation, two new control schemes are developed to suppress the near-wall vortical structures using the actuation of wall blowing/suction and obtain 16 % and 11% drag reduction, respectively.

关键词： active control Measurable wall information Near-wall streamwise vortices Turbulent drag reduction

active control of flow past an elliptic cylinder using an artificial neural network trained by deep reinforcement learning

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Applied Mathematics and Mechanics(English Edition) 2022年第12期43卷 1921-1934页

作者： Bofu WANG Qiang WANG Quan ZHOU Yulu LIU Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China Shanghai Frontiers Science Base for Mechanoinfomatic Shanghai UniversityShanghai 200072China School of Science Shanghai Institute of TechnologyShanghai 201418China

The active control of flow past an elliptical cylinder using the deep reinforcement learning(DRL)method is *** axis ratio of the elliptical cylinderΓvaries from 1.2 to 2.0,and four angles of attackα=0°,15°,30°,and 45°are taken into consideration for a fixed Reynolds number Re=*** mass flow rates of two synthetic jets imposed on different positions of the cylinderθ1andθ2are trained to control the *** optimal jet placement that achieves the highest drag reduction is determined for each *** a low axis ratio ellipse,i.e.,Γ=1.2,the controlled results atα=0°are similar to those for a circular cylinder with control jets applied atθ1=90°andθ2=270°.It is found that either applying the jets asymmetrically or increasing the angle of attack can achieve a higher drag reduction rate,which,however,is accompanied by increased *** control jets elongate the vortex shedding,and reduce the pressure ***,the flow topology is modified at a high angle of *** an ellipse with a relatively higher axis ratio,i.e.,Γ1.6,the drag reduction is achieved for all the angles of attack *** larger the angle of attack is,the higher the drag reduction ratio *** increased fluctuation in the drag coefficient under control is encountered,regardless of the position of the control *** control jets modify the flow topology by inducing an external vortex near the wall,causing the drag *** results suggest that the DRL can learn an active control strategy for the present configuration.

关键词： drag reduction deep reinforcement learning(DRL) elliptical cylinder active control

active control of wall-bounded turbulence for drag reduction with piezoelectric oscillators

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Chinese Physics B 2018年第7期27卷 397-403页

作者： Jian-Xia Bai Nan Jiang Xiao-Bo Zheng Zhan-Qi Tang Kang-Jun Wang Xiao-Tong Cui Department of Mechanics School of Mechanical EngineeringTianjin UniversityTianjin 300350China Deptartment of Mathematics Tianjin University Renal CollegeTianfin 301636China Tianjin Key Laboratory of Modern Engineering Mechanics Tianjin 300072China

An experimental investigation was performed for active control of coherent structure bursting in the near-wall region of the turbulent boundary layer. By means of synchronous and asynchronous vibrations with double piezoelectric vibrators, the influence of periodic vibration of the double piezoelectric vibrators on the mean velocity profile, drag reduction rate, and coherent structure bursting is analyzed at Reo = 2766. The case with 100 V/160 Hz-ASYN is superior to other conditions in the experiment and a relative drag reduction rate of 18.54% is exciting. Asynchronous vibration is more effective than synchronous vibration in drag reduction at the same voltage and frequency. In all controlled cases, coherent structures at large scales are regulated while the small-scale structures are stimulated. The fluctuating velocity increases significantly. A periodic regulating effect on the coherent structure can be seen in the ASYN control conditions at the frequency of 160 Hz.

关键词： turbulent boundary layer active control double piezoelectric vibrators

active control of structural vibration by piezoelectric stack actuators

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2005年第9期6卷 974-979页

作者：牛军川赵国群胡夏夏 School of Mechanical Engineering Shandong University Jinan 250061 China School of Material Science and Engineering Shandong University Jinan 250061 China College of Mechanical and Electrical Engineering Zhejiang University of Technology Hangzhou 310014 China

This paper presents a general analytical model of flexible isolation system for application to the installation of high-speed machines and lightweight structures. Piezoelectric stack actuators are employed in the model to achieve vibration control of flexible structures, and dynamic characteristics are also investigated. Mobility technique is used to derive the governing equations of the system. The power flow transmitted into the foundation is solved and considered as a cost function to achieve optimal control of vibration isolation. Some numerical simulations revealed that the analytical model is effective as piezoelectric stack actuators can achieve substantial vibration attenuation by selecting proper value of the input voltage.

关键词： Piezoelectric actuator Power flow active control

active control OF DYNAM IC RESPONSE OF LARGE DEFLECTION PLATES WITH PIEZO ELECTRIC ACTUATORS USING FINITE ELEMENT METHOD

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Chinese Journal of Aeronautics 1999年第4期12卷 197-204,221页

作者：高坚新沈亚鹏西安交通大学工程力学系陕西西安

The transientbehaviorofisotropic and hom ogeneousplateshasbeen a subjectofinterest. Thepresentinvestigation isconcerned w ith the largedeflection transientanalysisand controlofplates w ith piezoelectricsensorsand actuatorsunderapplied transverse loads. In this paper, the increm ental finite elem entequationsconsidering thegeom etricnonlinearity ofpiezoelectricsm artstructuresarede- veloped based on TotalLagrange approach by using the virtualvelocity increm entalvariationalprinci- ples. A four-node Mindlin plate elem ent w ith reduced and selective integration is adopted. The re- sulting increm entequationsare solved by using New m ark'sdirectintegration approach. Transientre- sponse ofplatesw ith piezoelectricsensorsand actuators subjected to transverse dynam ic loading isin- vestigated. The active dam ping isintroduced on the platesby coupling a negativevelocity feedback al- gorithm in a closed controlloop. The num ericalresults show thatpiezoelectric actuators can produce significant dam ping and suppress transient vibration effectively. Finally, the effects of the num ber and locations ofthe piezoelectric actuatorson the controlsystem are also investigated.

关键词： geom etrically nonlinearity active control finite elem ent

active control of supersonic/hypersonic aeroelastic flutter for a two-dimensional airfoil with flap

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Science China(Technological Sciences) 2011年第8期54卷 1943-1953页

作者： ZHAO Na School of Astronautics Harbin Institute of Technology PO Box 137 Harbin 150001 China

The flutter, post-flutter and active control of a two-dimensional airfoil with control surface operating in supersonic/hypersonic flight speed regions are investigated in this paper. A three-degree-of-freedom dynamic model is established, in which both the cubic nonlinear structural stiffness and the nonlinear aerodynamic load are accounted for. The third order Piston Theory is employed to derive the aerodynamic loads in the supersonic/hypersonic airflow. Nonlinear flutter happens with a phenomenon of limit cycle oscillations (LCOs) when the flight speed is less than or greater than linear critical speed. The LQR approach is employed to design a control law to increase both the linear and nonlinear critical speeds of aerodynamic flutter, and then a combined control law is proposed in order to reduce the amplitude of LCOs by adding a cubic nonlinear feedback control. The dynamic responses of the controlled system are given and used to compare with those of the uncontrolled system. Results of simulation show that the active flutter control method proposed here is effective.

关键词： flutter/post flutter active control supersonic/hypersonic flow 2-D airfoil nonlinearity

active control of circular cylinder flow by affiliated rotating cylinders

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Science China(Technological Sciences) 2013年第5期56卷 1186-1197页

作者： WANG JianSheng XU YuanXin TIAN YongSheng Key Laboratory of Efficient Utilization of Low and Medium Grade Energy MOESchool of Mechanical EngineeringTianjin University

This study puts forward an active control method for circular cylinder flow by placing two small affiliated rotating cylinders adjacent to the main cylinder, and their effects on the drag and lift forces acting on the main cylinder as well as the heat trans- fer effectiveness are numerically investigated. According to the diameter of the main cylinder the Reynolds number is chosen as Re=200. The well-proven finite volume method is employed for the calculation. The code is validated by comparing the present computed results of flow passing an isolated rotating cylinder with those available from the literature. To describe the present control model, two parameters are defined： the rotation direction of the two small cylinders （including co-current rota- tion and counter-current rotation） and the dimensionless rotation rate a. In the simulation, the rotation rate a varies from 0 to 2.4. The results indicate that the optimum rotation direction of the subsidiary cylinders, which is beneficial to both drag reduc- tion and beat transfer enhancement, is the co-current rotating （the upper affiliated cylinder spins clockwise and the lower affili- ated cylinder spins counter-clockwise）. We observe noticeable suppression of the vortex shedding and favorable reduction of the fluid forces acting on the main cylinder as the rotation rate increases. Besides, the pressure and viscous components of the drag force are analyzed. Energy balance between energy cost for activating the rotating cylinders and energy saving by the momentum injection is considered. In addition, the influence of the affiliated rotating cylinders on heat transfer is also investi- gated. The average Nusselt number is found to increase with the rotation rate.

关键词： active control affiliated cylinders vortex suppression drag and lift forces Nusselt number

active control scheme for improving mass resolution of film bulk acoustic resonators

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Applied Mathematics and Mechanics(English Edition) 2011年第6期32卷 749-756页

作者：贺学锋刘兴印显方温志渝陈可万 Key Laboratory of Optoelectronic Technology and Systems of Ministry of Education of China Chongqing University Microsystem Research Center Chongqing University

High mass resolution of sensors based on film bulk acoustic resonators （FBARs） is required for the detection of small molecules with the low concentration. An active control scheme is presented to improve the mass resolution of the FBAR sen- sors by adding a feedback voltage onto the driving voltage between two electrodes of the FBAR sensors, The feedback voltage is obtained by giving a constant gain and a constant phase shift to the current on the electrodes of the FBAR sensors. The acoustic energy produced by the feedback voltage partly compensates the acoustic energy loss due to the material damping and the acoustic scattering, and thus improves the quality factor and the mass resolution of the FBAR sensors. An explicit expression relating to the impedance and the frequency for an FBAR sensor with the active control is derived based on the continuum theory by neglecting the influence of the electrodes. Numerical simulations show that the impedance of the FBAR sensor strongly depends on the gain and the phase shift of the feedback voltage, and the mass resolution of the FBAR sensor can greatly be improved when the appropriate gain and the phase shift of the feedback voltage are used. The active control scheme also provides an effective solution to improve the resolution of the quartz crystal microbalance （QCM）.

关键词： film bulk acoustic resonator sensor active control impedance resolution