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    2023,21(12):1-17, DOI: 10.6052/1672-6553-2023-132
    Abstract:
    This paper investigates the event-triggered output feedback adaptive fuzzy fault-tolerant control problem for switched nonlinear systems with actuator faults. Firstly, A mode-dependent state observer is established to estimate unmeasured states. Fuzzy logic systems are employed to approximate the unknown uncertainties. The constructed adaptive fuzzy fault-tolerant event-triggered controller can reduce the usage of the communication resources. Then, by multi-Lyapunov functions and average dwell time method, it is proved that all states of the closed-loop systems are SGGUB. In addition, zeno phenomenon can be excluded. Finally, the effectiveness of the method is verified by simulation result.
    2023,21(12):18-32, DOI: 10.6052/1672-6553-2023-133
    Abstract:
    In-orbit capture of space objects is a crucial aspect of spacecraft servicing, whether it involves space debris removal or spacecraft maintenance. The challenging task of capturing objects in space is the primary focus of this article. This paper provides a comprehensive review of the dynamics and control issues related to space robot capture. It begins by introducing major space robot programs both domestically and internationally. Subsequently, it delves into the dynamics and control problems during the pre-capture, mid-capture, and post-capture phases. It is hoped that the content of this article will be beneficial to scholars engaged in space robot technology research.
    2023,21(12):33-48, DOI: 10.6052/1672-6553-2023-134
    Abstract:
    Highly explosive jumping is one of the survival keys to the organism evolution over the course of billions of years. This movement helps organisms to achieve flexible movement functions under various unstructured conditions. Through an in-depth understanding of biological jumping mechanism, the small-scale jumping robot has made great progress in function and performance. Taking the four stages of biological jumping movement (preparation for take-off, take-off, flight and landing) as the main line, this paper reviews the behavioral principle of organisms, introduces the dynamic characteristics and technology of the corresponding small-scale jumping robots, summarizes the challenges of existing research, and finally discusses the future development and potential of jumping robots.
    2023,21(12):49-65, DOI: 10.6052/1672-6553-2023-135
    Abstract:
    As a representative of the automation and intelligence era, robot technology has become the focus of the intelligent control research, Various robot intelligent control technologies have been developed, Robots are more and more used to achieve some complex contact-rich interaction tasks. This paper chooses robot complex contact-rich interaction tasks as a topic, combining the research of robot reinforcement learning, to make a survey of research about the robot contact-rich interaction tasks based on reinforcement learning. We review some representative researches of implementing reinforcement learning in robot contact-rich interaction tasks, analyze the existing problems in these researches, summarize the optimization methods of solving these problems to improve the experimental effects, and finally make a prospect on the future of robot contact-rich tasks.
    2023,21(12):66-74, DOI: 10.6052/1672-6553-2023-136
    Abstract:
    Continuum robots, due to their characteristics of flexible and large deformations, as well as dexterous mobility, have become a development trend for enhancing safety and interactivity of robots in the future. Digital twin is an important technical support to achieve coexistence and integration among robots, environments and humans. This article focuses on the research of tensegrity flexible manipulator and combines technologies such as digital twin and virtual simulation to enable deep integration of the tensegrity manipulator in virtual and physical spaces. A data communication architecture is established to achieve real time data transmission, thereby enhancing the collaborative efficiency between the flexible manipulator and humans. Moreover, dynamic obstacle avoidance in complex environments is considered through collision detection feedback. Furthermore, a tensegrity flexible manipulator digital twin system based on dynamics is developed, and the effectiveness of the constructed system is verified by the experiments on bidirectional control of the tensegrity manipulator between virtual and physical domains. This research provides a reference for remote intelligent monitoring and control of other robots.
    2023,21(12):75-84, DOI: 10.6052/1672-6553-2023-137
    Abstract:
    The article investigates the differential flatness of a swarm of unmanned aerial vehicles (UAVs), provides the differential flatness mapping for relative motion, and uses this as a foundation to design a distributed formation controller. In terms of motion planning, it generates real-time desired formation trajectories and configurations by solving constrained optimization problems. In terms of motion control, it utilizes the differential flatness mapping to map motion commands into desired states and control inputs for each UAV. Subsequently, it designs a distributed formation controller based on local error feedback to track the desired motion trajectories. To address the stability of collective motion, this article employs Lyapunov stability theory to prove the stability of the closed-loop system and provides conditions for selecting control parameters. Finally, simulations validate the effectiveness of the formation control method in an unknown obstacle environment.
    2023,21(12):85-91, DOI: 10.6052/1672-6553-2023-138
    Abstract:
    In order to better simulate practical conditions, a rigid flexible coupling model of a designed duck inspired robot was established using Hypermesh and Adams which are finite element software and dynamics software respectively. The dynamic stress and deformation of the shank were calculated. And two factors impact on the kinematics parameters of the webbed foot were analyzed , namely the deformation of shank and the friction coefficient of the leg joints. The results showed that during the operation of the robot, the shank met the requirements for strength and stiffness. The kinematics parameter error of webbed feet caused by the deformation of the shank will affect the accuracy during motion. Lubricating at joints can decrease the shock of robot. The simulation results can provide reference for the subsequent optimization of robot structures.
    2023,21(12):92-102, DOI: 10.6052/1672-6553-2023-139
    Abstract:
    Aiming at the path planning and control problem of multi-mobile robot gathering, this paper proposes a path planning strategy based on an improved fast marching square method. Firstly, the segmentation function is applied to improve the velocity map to realize safer and more efficient path planning, which can map the velocities on the fast marching grid map to the real robot velocities and reduce the redundant paths generated by the traditional fast marching square method in the process of backtracking the paths; then, for the three task requirements of minimizing the total energy consumption in the gathering process of the multi-mobile robots, maximizing the space near the gathering point, and minimizing the total energy consumption of the gathering process under the constraints of the gathering formation, different objective functions are analyzed and designed to give the gathering point of multi-mobile robots and the corresponding paths, which demonstrates the validity of this paper's method as well as its applicability in different scenarios. Finally, on the basis of the vehicle dynamics model, trajectory tracking simulation experiments are carried out using the model predictive control with the improved speed on the fast marching grid map as the robot's reference speed, and the results show that the tracking error is reduced, which verifies the effectiveness of the improved speed field of this paper, and it can be applied to the gathering path planning and control of multi-mobile robots in the real environment.
    2023,21(12):103-109, DOI: 10.6052/1672-6553-2023-140
    Abstract:
    With the development of social productivity and the increasing demands of society, mobile manipulators have attracted extensive attention from academia and industry due to their advantages. The industry expects mobile manipulators to accomplish more complex and flexible tasks. However, in many work scenarios, a single mobile manipulator has limited degrees of freedom and payload capacity, leading to the emergence of multi-mobile manipulator systems. This paper establishes the dynamic model of a multi-mobile manipulator system and conducts stability analysis on the dynamic equations. Firstly, the dynamic equation of a single mobile manipulator is established using the Lagrange equations. The correctness of the model is verified by comparing the result obtained from multi-body dynamics software with the numerical calculation result of the dynamics model. Subsequently, the dynamic equations of multiple mobile manipulators and the dynamic equations of the manipulated object are combined to obtain the closed-form dynamic equations of the multi-mobile manipulator system. Then, a Lyapunov function is designed based on joint position error and velocity error, and a control law for joint torques is obtained using the backstepping method. Finally, in the simulation using multi-body dynamics software, the effectiveness of the control law is examined by checking whether the trajectory can track the desired signal.
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    2014,12(3):193-200, DOI: 10.6052/1672-6553-2014-046
    [Abstract] (2741) [HTML] (0) [PDF 748.46 K] (5650)
    Abstract:
    The spacecraft's ability to adapt to the harsh dynamics environment is critical for the whole space mission. Vibration test control technology is the key part of the dynamic environment test. The current progress, fundamental principles and key techniques development level of the spacecraft and vibration control algorithms overseas were analyzed. The basic ideas, effective ways and suggestions were given to domestic following research.
    2014,12(1):18-23, DOI: 10.6052/1672-6553-2013-068
    [Abstract] (2674) [HTML] (0) [PDF 1.13 M] (5370)
    Abstract:
    The electromechanical coupling model of cantilevered piezoelectric harvester was developed by considering the nonlinearities of piezoelectric material, based on Hamilton theory, Rayleigh-Ritz method, Euler-Bernoulli beam theory and constant electrical field across the piezoelectric element. The response characteristics of the system were investigated numerically, and the influences of piezoelectric material nonlinear coefficient on the system response were analyzed. By exploring the nonlinear characteristics of the piezoelectric vibrator near the resonant frequency, the nature of the multi-solutions and jump phenomena in the resonance region was revealed. The results were verified experimentally. which provides a theoretical basis for the study of nonlinear mechanism of piezoelectric power generation system.
    2017,15(5):385-405, DOI: 10.6052/1672-6553-2017-039
    [Abstract] (1695) [HTML] (0) [PDF 1.91 M] (5184)
    Abstract:
    In this review article, the growth and related academic communications in the dynamics of multibody systems are firstly surveyed. Then, the recent advances in the numerical algorithms for solving the dynamic equations of flexible multibody systems, the contact/impact dynamics of flexible multibody systems and the deployment of flexible space structures are systematically reviewed, together with several open problems of concern. Finally, some suggestions are made for the prospective researches on the dynamics of flexible multibody systems.
    2014,12(3):243-247, DOI: 10.6052/1672-6553-2014-054
    [Abstract] (2370) [HTML] (0) [PDF 1.07 M] (5022)
    Abstract:
    Random vibration test is very important to the aerospace equipment. The windage of ASD outside the frequency bandwidth was analyzed. The reason, premonition, affection and effective way were given. And the commonly used random vibration test and vibration test metrology standard for the ASD outside the frequency bandwidth were analyzed.
    2015,13(5):361-366, DOI: 10.6052/1672-6553-2014-064
    [Abstract] (1087) [HTML] (0) [PDF 826.19 K] (4992)
    Abstract:
    Dynamic and control systems often contain uncertain parameters that may result in uncertain predictions. In the interest of quantifying the effects of parameter uncertainties on response variability, this paper develops a stochastic response surface based method for the sensitivity analysis of uncertain parameters. Stochastic response surfaces were firstly constructed to describe the explicit relationships between uncertain parameters and responses. Then partial derivations were performed on the mathematical expressions of stochastic response surfaces in order to obtain sensitivity indices that simultaneously embody the effects of parameter means and standard deviations. Lastly, the developed method has been verified against a numerical cantilever beam containing uncertain geometric and material parameters. The sensitivity analysis results were compared with those given by the analysis of variance method.
    2016,14(2):97-108, DOI: 10.6052/1672-6553-2015-009
    [Abstract] (2135) [HTML] (0) [PDF 1.87 M] (4666)
    Abstract:
    Based on the current research status of multi agents system control theory and technology, the paper makes a detailed overview for unmanned ground systems. From two aspects of behaviour and task cooperative control for multi agents, the relevant theory and application problem is discussed. Moreover, some existed open problems are presented and a possible future development is proposed. For unmanned ground systems, cooperative control will be of great importance in promoting social and military benefits and maximizing the executive function of ground mission.
    2014,12(3):225-229, DOI: 10.6052/1672-6553-2014-051
    [Abstract] (2186) [HTML] (0) [PDF 1.38 M] (4647)
    Abstract:
    Based on the staggered solution procedure of ANSYS and CFX software, the fluid structure coupling response of projectile during tail slapping has been researched. Structural response was simulated by using FEM and flow field was simulated by using inhomogeneous model and SST turbulence model. Finally, the influences of fluid structure coupling effect have been analyzed and the change law of body stress has been given.
    2014,12(3):269-273, DOI: 10.6052/1672-6553-2014-043
    [Abstract] (3026) [HTML] (0) [PDF 336.30 K] (4608)
    Abstract:
    Aiming at the problem that the longitudinal modes of structural system of rocket need to be identified from its integral modes in engineering, a method that automatically identifies the longitudinal modes of structural system of rocket was proposed according to the theory of modal effective mass. Taking the vibration characteristics of system with lumped mass as a computing example, applying the finite element software, the beam model of system with lumped mass was established, and the longitudinal modes of the system were automatically identified based on the method. Compared with the system modal information calculated by the method of modal analysis, this automatic identification method not only can accurately identify the longitudinal modes of vibrating system, but also has automatic and high efficiency identification feature. It provides a theoretical basis for the dynamic model of POGO vibrating system in liquid rockets and other model of engineering systems to be accurately and promptly established.
    2012,10(1):21-26, DOI:
    Abstract:
    A discrete finite dimensional dynamical model was built to describe the space large overall motion of tethered satellite system with an infinite dimensional viscoelastic tether in a long time. The tethered satellite system is a complex nolinear dynamic system. Considering the tether’s viscoelasticity, distributed mass and space form, the established improved bead model can meticulously describe the tether’s vertical and horizontal vibration. According to tether’s characteristic of tensile and not compressive, the slack tether unit model was set up to accurately reflect real stress of tether. The determination of the number of degrees of freedom of the system was studied. Based on numerical integral calculation, the dynamic response was obtained via numerical simulation of the deployment, retrievement and retainment process of tethered satellite system in a long time. The result is convergent. The simulation proves the important role of the stable equilibrium position in the dynamics of tethered space system.
    2008,6(4):301-306, DOI:
    Abstract:
    The problem of P and PI feedback control to a time delay system was investigated,with the emphasis on the determination of the feedback gains that ensured the asymptotical stability of the delayed system. By means of Lambert W function,the feedback gain of P control can be expressed explicitly,so that the optimal feedback gain can be easily obtained. For the system under a PI control,the stable region of the feedback gains was determined on the basis of stability switches and D subdivision,and the optimal feedback gains that enabled the system to admit maximal stable margin were figured out numerically by using Lambert W function. From the viewpoint of computation,the present method is much simpler than the available methods.
    2014,12(2):183-187, DOI: 10.6052/1672-6553-2014-025
    [Abstract] (1155) [HTML] (0) [PDF 811.52 K] (4202)
    Abstract:
    PMSM due to little harmonic, high precision torque, commonly is used in the servo system and the high performance speed control system. In this paper,the physical model of PMSM is simplified and the mathematical model of the motor is established in order to facilitate research.Thispaper uses id=0 control manner which is the simplest manner is vector control methods,motor electromagnetic torque equation is established based on rotor field oriented vector control.The system model, speed and current control block are build and simulated with MATLAB/Simulink.Simulation results shows that the waveform is consistent with thoretical analysis,the model has fast response and small overshoot.The system runs stably with good dynamic and static characteristics. The simulation makes full use of modularization design. All the parameters and their influence on the system can be changed and observed.It also can easily validate the control strategies and select the most suitable one. So this kind of simulation is good for system design and adjusting and validating.
    2013,11(1):12-19, DOI: 10.6052/1672-6553-2013-003
    [Abstract] (2027) [HTML] (0) [PDF 530.95 K] (4163)
    Abstract:
    The dynamics of the whole aero-engine system has always been the important part that cannot be neglected in the research and design of the engine, as the framework of the engine, the vibration of the casing directly reflects the level of the whole aero engine vibration. In this paper, an analysis was made on the research of the problems and fault classification of aero-engine casing dynamics, and an overview was made on the research of present situation, development trend, problems and solutions of the domestic and foreign of casing dynamics, which expanded the present situation of the Inclusiveness problems of aero-engine casing dynamics. Finally, some proposals were put forward for the development of the casing dynamics suitable for our country aero-engine technology level.
    2013,11(4):357-362, DOI: 10.6052/1672-6553-2013-041
    [Abstract] (1192) [HTML] (0) [PDF 350.50 K] (3962)
    Abstract:
    At present, the main task of designing a mounting system of automotive engine powertrain is to select appropriate stiffness, position and angle of mounting components so that free-vibration modal frequency of the mounting system can avert from the exciting-force frequency at the idle speed of the engine and the natural frequency of vibration of the vehicle body and that the decoupling degree of each mode shape is increased as far as possible, so as to improve the vibration-isolation effect of the mounting system. The design of a mounting system based on strict decoupling at predetermined frequencies is to make the modal frequencies of the designed mounting system completely equal to the frequencies predetermined in accordance with the frequency planning of automotive design, and to enable strict decoupling of each mode shape of each mode, i.e., the decoupling degree of vibration energy in every direction equals to 1. Based on a free-vibration equation for a mounting system, this paper presents an equation system for designing a mounting system with strict decoupling at predetermined frequencies, provides a solving method for this equation system by using the theory of generalized inverse matrix or method of constructing function, so as to provide an optimal design method more efficient and simpler than the current modal optimization method of mounting system. Relevant example has validated the correctness of equations and solving method of the strict-decoupling design at predetermined frequencies.
    2014,12(3):205-209, DOI: 10.6052/1672-6553-2014-059
    [Abstract] (1975) [HTML] (0) [PDF 467.15 K] (3922)
    Abstract:
    This paper investigated the passive nonlinear vibration control method used for energy absorbing in structures of spacecrafts. The structure and the dynamic model of the nonlinear energy sink which could adapt to the space environment were proposed. As nonlinear spring could not be acquired easily in reality, we proposed a new design for the NES based on employing an asymmetric NES force which was generated by two pairs of aligned permanent magnets. Then, the dynamic model for a cantilever beam structure coupled with nonlinear energy sink had been built theoretically. In addition, the passive vibration suppression effect of the nonlinear energy sink on the cantilever beam structure under transient excitation had been analyzed through Galerkin method and numerical analysis method. The results showed that the NES acquired up to 92% dissipation of the system energy imposed by shock excitation, hence the NES could adapt to the space environment and improve the reliability of space system.
    2014,12(3):283-288, DOI: 10.6052/1672-6553-2014-061
    [Abstract] (2745) [HTML] (0) [PDF 479.50 K] (3890)
    Abstract:
    A method was presented to analyze the nonlinear flutter. Based on this method, the flutter characteristics of the high aspect wing were illustrated. The numerical results show that the flutter speed is decreased when the first horizontal bending mode involved. Secondly, this study discussed how the main direction of the composite influenced the character of the nonlinear vibration and flutter, and established the method of the flutter clipping to the high aspect wing. And the result shows that the stiffness of structure can be changed by changing the main direction of the composite. It mainly changes the horizontal bending mode, makes the main direction tend to the trailing edge, and then makes the section line move to the leading edge. Further analyzing the nonlinear flutter reveals that it is the changing of the horizontal bending mode that causes the flutter speed change obviously. And by the section line of this mode moves ahead, the flutter speed will become larger. In the study, two examples were illustrated to validate its truthiness.
    2016,14(3):247-252, DOI: 10.6052/1672-6553-2015-052
    [Abstract] (1632) [HTML] (0) [PDF 2.18 M] (3831)
    Abstract:
    Tires are the only carrier of the contact between the vehicle and road surface. Their mechanical property is important for analysis and control on the vehicle dynamic response. At present, the tire simulation mostly focuses on the steady state model. But it can not describe the dynamic characteristic of the tire accurately. Therefore, it plays a significant role to add the dynamic tire model in the vehicle dynamics simulation. The tire friction model in the multi body dynamical software ADAMS is static, where the friction is regarded as a static value. However, in actual, the friction between the tire and road surface is dynamic, and it should be a dynamic function of the relative velocity and displacement. To this end, in this paper, the dynamic tire LuGre model using the Matlab/Simulink software is constructed. Through connecting the interface with Adams/Car, co simulation between the vehicle model and the simulink tire model is carried out in order to achieve the dynamic contact between tire and road and improve the accuracy of vehicle system analysis.
    2014,12(1):36-43, DOI: 10.6052/1672-6553-2013-110
    [Abstract] (1801) [HTML] (0) [PDF 2.22 M] (3711)
    Abstract:
    The coupling nonlinear dynamic model of dual rotor system was established by using finite element method, and then the critical speed of revolution and mode shape were calculated by using the software MATLAB. In addition, the unbalance responses of dual rotor system were studied, and the vibration performances in different speeds of dual rotor casing systems were obtained. The research provides a theoretical basis for the design of the dual rotors system in engineering.
    2014,12(3):253-258, DOI: 10.6052/1672-6553-2014-056
    [Abstract] (1768) [HTML] (0) [PDF 1.00 M] (3675)
    Abstract:
    Taking account of the structural stiffness and the low order vibration frequencies, two schemes of multi-objective topology optimization were proposed to obtain the best aircraft lifting-surface structural design. Based on penalized density theory, the scheme one (named as constrain method) is to convert the multi-objective optimization to single-objective optimization by considering the minimum structural mass as the objective with constraints of reference points displacements and the low order vibration frequencies. The scheme two (named as the combination of constrain method and criterion function method) settles the multi-objective optimization by defining combined compliance index (CCI) as the objective, with the constraints of volume fraction and the low order vibration frequencies. The CCI is the function of structural compliance and low order vibration frequencies. Numerical results demonstrate the proposed schemes not only realize reducing the structural mass but also raise the first and second order frequencies.
    2014,12(3):201-204, DOI: 10.6052/1672-6553-2014-048
    [Abstract] (2057) [HTML] (0) [PDF 296.79 K] (3568)
    Abstract:
    Non-linear factors cannot be avoided in the design of aircraft structures. In this paper, a two-degree-of-freedom airfoil and cubic stiffness nonlinearities in pitching degree-of-freedom operating in supersonic flight speed regimes has been analyzed. The averaging method and the theory of flutter were used to analyze the nonlinear dynamic system of the dualistic airfoil in the supersonic flow. Then the correctness of the theoretical calculation was verified by numerical calculation, and the analysis result was given.
    2014,12(1):62-66, DOI: 10.6052/1672-6553-2013-097
    [Abstract] (1343) [HTML] (0) [PDF 832.87 K] (3400)
    Abstract:
    A spline finite point method was presented to study the natural frequency of arch. The displacement mode shape function of the arch free vibration was simulated with a linear combination of cubic B spline. The free vibration frequency equation of arch structures was derived according to Hamilton principle, in which the effect of the dead load was considered. Meanwhile, the effect of the dead load on the natural frequency of arch structures was analyzed. The results show that the natural frequency of arch is reduced. The effect of influence depends on the stiffness of the arch itself. When the arch stiffness is certain, the bigger the rise span ration and the radius to thickness ration, the higher the effect of the dead load on the natural frequency of arch structures.

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