共查询到20条相似文献，搜索用时 218 毫秒
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使用Pro/E三维建模软件和ANSYS/LS-DYNA动力学仿真软件相结合对谐波齿轮传动性能进行动力学仿真分析。利用Pro/E软件对谐波齿轮的各个组件进行三维建模,将建好的杯形柔轮与刚轮刚柔耦合模型导入到ANSYS有限元软件中,进行谐波齿轮的动态有限元接触分析,得出柔轮在运动循环内的不同时刻,杯形柔轮整体受到的应力、变形分布规律。研究表明,利用Pro/E和ANSYS/LS-DYNA动力学软件相结合,能够准确对杯形柔轮进行动力学仿真计算,使得仿真结果更加贴近实际,为谐波齿轮的可靠性设计提供了基础。 相似文献
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本文基于有限元分析方法,采用适合中、小型光学元件的周边支撑结构形式,进行了某星载温室气体探测仪大平面反射式闪耀光栅支撑结构的设计。通过对光栅组件进行有限元建模,以及固有模态、静力学、动力学、光机热集成分析,优化了支撑结构设计,使得光栅组件基频〉300Hz,在±5℃均匀温度变化和1g重力耦合作用下,光栅刻划表面波前面形精度仍符合光学设计要求。最终工程分析结果表明：大平面反射式闪耀光栅的支撑结构设计是合理的,光栅组件固有一阶频率高,抗重力变形能力、抗震性能均能满足仪器总体设计指标要求,通过选用不同热膨胀系数的结构材料及合理设计零件配合尺寸等消热设计手段有效抑制了光栅支撑结构的变形对光栅结构的扭曲作用。 相似文献
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螺旋锥上的齿轮是重要的基础原价,在其设计、加工的过程中进行参数的调整会直接影响齿轮的传动性能。本文对齿轮的设计和加工原理进行研究,在建立数学模型后,对影响齿面和机床调整参数的误差进行研究。 相似文献
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介绍了基于uG的齿轮参数化建模思路，用数学方法建立渐开线单齿齿廓的曲线方程，将齿廓的曲线方程转化uG的表达式，利用uG的强大的参数化设计工具，完全实现了渐开线直齿轮圆柱齿轮的全参数化精确建模，建模结果能直接用于有限元分析和机构仿真、数控加工等都需要。 相似文献
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我国生产的采煤机大多采用齿轮—销轨式机构,根据接触理论,齿轮与销轨相啮合时将会产生较大接触应力,成为该机构点蚀和磨损的主要原因。现采用参变量变分原理及基于此原理的有限元参数二次规划法来求解齿轨弹性接触问题,经过大量的计算,求出了行走齿轮和销轨的内部应力和齿轨接触力。 相似文献
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Zebin Yang Qifeng Ding Xiaodong Sun Huimin Zhu Chengling Lu 《Journal of The Franklin Institute》2021,358(7):3701-3725
In order to improve the anti-disturbance performance of a bearingless induction motor (BIM) control system, a fractional-order sliding mode control (FOSMC) strategy based on improved load torque observer is proposed on the basis of the sliding mode speed regulation system. Using the information memory and genetic characteristics of the fractional calculus operator, the fractional integral term of the speed error is introduced in the design of the traditional sliding surface, which reduces the influence of disturbance on the speed regulation system. The fractional-order sliding mode control law is derived based on the BIM mathematical model, and the stability of the control law is proved by Lyapunov theorem. An improved observer is constructed based on the BIM state equations, and the real-time observed load torque is introduced into the fractional-order sliding mode controller. To improve the observer's convergence speed, the proportional integral form is used to replace the integral form in the traditional reduced order load observer. And the state error feedback coefficients of the improved load observer are calculated. Both simulation and experimental results verified the effectiveness of the proposed control strategy. 相似文献
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Adaptive sliding mode tracking control for a flexible air-breathing hypersonic vehicle 总被引：2，自引：0，他引：2
Xiaoxiang Hu Ligang Wu Changhua Hu Huijun Gao 《Journal of The Franklin Institute》2012,349(2):559-577
This paper is concerned with the adaptive sliding mode control (ASMC) design problem for a flexible air-breathing hypersonic vehicle (FAHV). This problem is challenging because of the inherent couplings between the propulsion system, the airframe dynamics and the presence of strong flexibility effects. Due to the enormous complexity of the vehicle dynamics, only the longitudinal model is adopted for control design in the present paper. A linearized model is established around a trim point for a nonlinear, dynamically coupled simulation model of the FAHV, then a reference model is designed and a tracking error model is proposed with the aim of the ASMC problem. There exist the parameter uncertainties and external disturbance in the model, which are not necessary to satisfy the so-called matched condition. A robust sliding surface is designed, and then an adaptive sliding mode controller is designed based on the tracking error model. The proposed controller can drive the error dynamics onto the predefined sliding surface in a finite time, and guarantees the property of asymptotical stability without the information of upper bound of uncertainties as well as perturbations. Finally, simulations are given to show the effectiveness of the proposed control methods. 相似文献
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Two algorithms based on an integral equation formulation of the buckling optimization problem are formulated and implemented. The objective of the optimization is to maximize the buckling load of an elastically restrained column by optimally designing the cross-sectional area subject to a minimum cross-section or maximum stress constraint. The first approach involves solving the resulting integral equations iteratively taking into account the boundary conditions, the optimality criterion and the imposed constraints. In the second approach an iterative finite difference approximation scheme is developed.The column is elastically restrained at both ends which produce the simple support and clamped end conditions for the limiting cases leading to the optimal design of columns under general boundary conditions. The above problems do not have analytical solutions due to the complexity of the boundary conditions, constraints and the optimality conditions necessitating the formulation of computational schemes for their solution. Several numerical results are given and compared with available results in the literature. Moreover the accuracy of the methods is studied by comparing the iterative solutions with finite element ones and with exact results when available. 相似文献
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Recently, series elasticity has been realized using pneumatics in human-robot interaction systems. Pneumatic circuits provide not only a flexible power transmission, but also the elastic element in a series elastic actuator (SEA). Pneumatic series elastic systems involve more than twice the number of parameters that influence system behaviors in comparison with rigid robotic systems. In this study, a position controller that eliminates the need of identifying a system model by employing the time delay estimation (TDE) technique is proposed for pneumatic SEA systems. The TDE technique is effective in compensating for system dynamics and all uncertainties involved in system behaviors without imposing computation load. TDE error is cancelled out through a learning way, which improves control performance and leads to asymptotic stability. A simulation study demonstrates the robustness of the proposed controllers against uncertainties imposed on the motor system as well as uncertainties on the end-effector. The simulation shows the efficacy of the learning compensation for TDE error. 相似文献
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《Journal of The Franklin Institute》2022,359(15):7847-7865
The tracking control based on output feedback for a category of flexible-joint robot (FJR) systems is investigated in this brief. Control performance of the systems is inevitably bearing the brunt of various unknown time-varying disturbances, which can be categorized to be matched and mismatched and generally cover internal parameter uncertainties, couplings, unmodelled dynamics, and external load or changing operating environments. To cope with these disturbances, the mismatched disturbances are first transferred to the matched ones by a flatness method, which eliminates the computational cost of estimating mismatched disturbances. Then, a generalized proportional integral observer (GPIO) is constructed to estimate the unavailable states and disturbances. By integrating the estimated disturbance and states provided by the GPIO, a novel dynamic sliding surface is constructed. Finally, a continuous sliding mode control (CSMC)-based output feedback control framework is further designed. The presented control strategy only requires link position information and is continuous, which can effectively reduce the chattering driven by the high-frequency switching item in the traditional SMC method. Asymptotic convergence of output tracking error is guaranteed by theoretical analysis under some mild conditions. Comparative tests on a two-link FJR verify the claimed control performance. 相似文献
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利用级数展开法和Laplace--Fourier变换推导了文克尔地基上无限长板在半波正弦瞬态荷载作用下位移和应力的解析解。计算和分析了板的位移响应情况，并和弹性地基静荷载情况的位移进行了比较，讨论了荷载作用时间、地基参数及板参数等对位移响应的影响。对路面设计、品质评价及破坏机理分析有重要意义。 相似文献
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《Journal of The Franklin Institute》2023,360(5):3633-3656
In the electric driving system, the measurement of the motor speed error becomes more and more important, which has an impact on the system vibration suppression. In this paper, based on the single-neuron adaptive PID control method, the dual-inertia system considering gear friction torque is modeled and studied. Firstly, the dual-inertia system with gear friction is established, and dynamic differential equations of it are derived; Then, the comprehensive meshing stiffness and the time-varying friction torque of the gear system are deduced; Next, the Ziegler-Nichlos frequency domain response method is adopted to obtain the parameters of the PID controller. The control methods including the PID, Fuzzy-PID with DOB and single-neuron adaptive PID are utilized to adjust the motor speed of the system; Finally, the effects of gear friction, the moment of inertia of load and control methods on motor speed and system error are analyzed. 相似文献
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Bifurcation theory is commonly used to study the dynamical behavior of ecosystems. It involves the analysis of points in the parameter space where the stability of the system changes qualitatively. The type of bifurcation that associates equilibria with periodic solution is called Hopf bifurcation. In this paper, a life energy system dynamic model of two components with multiple delays is presented. It is shown that the interaction parameters of the delayed ecosystem play a fundamental role in classifying the rich dynamics and bifurcation phenomena. Regarding the combined interaction parameter as a bifurcation parameter, the bifurcation values in the parameter plane are displayed. The direction of the Hopf bifurcation and the stability of the bifurcating periodic solutions are determined by applying the normal form theory and the center manifold theorem. Moreover, the amplitudes of oscillations always increase as the interaction parameters increase, while the robustness of periods occurs as the interaction parameters vary. From an ecological point of view, the existence of Hopf bifurcation expresses periodic oscillatory behavior of the life energy system. 相似文献
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Electroosmotic flow (EOF) with two or more fluids is commonly encountered in various microfluidics applications. However, no investigation has hitherto been conducted to investigate the hysteretic or flow direction-dependent behavior during the displacement flow of solutions with dissimilar ionic species. In this investigation, electroosmotic displacement flow involving dissimilar ionic solutions was studied experimentally through a current monitoring method and numerically through finite element simulations. The flow hysteresis can be characterized by the turning and displacement times; turning time refers to the abrupt gradient change of current-time curve while displacement time is the time for one solution to completely displace the other solution. Both experimental and simulation results illustrate that the turning and displacement times for a particular solution pair can be directional-dependent, indicating that the flow conditions in the microchannel are not the same in the two different flow directions. The mechanics of EOF hysteresis was elucidated through the theoretical model which includes the ionic mobility of each species, a major governing parameter. Two distinct mechanics have been identified as the causes for the EOF hysteresis involving dissimilar ionic solutions: the widening/sharpening effect of interfacial region between the two solutions and the difference in ion concentration distributions (and thus average zeta potentials) in different flow directions. The outcome of this investigation contributes to the fundamental understanding of flow behavior in microfluidic systems involving solution pair with dissimilar ionic species. 相似文献