雷达仿生动力装置机电液系统协同仿真技术

雷达仿生动力装置是一个复杂的机、电、液一体化系统,利用单个仿真软件很难实现对其特性的准确描述。为了研究仿生动力装置的动力学特性,文中采用ADAMS、HyPneu及MATLAB软件分别建立系统的机械、液压和控制模型,并运用软件接口技术在MATLAB/Simulink环境中建立机电液系统的协同仿真平台,最终实现了对仿生动力装置机电液系统的协同仿真。仿真结果表明,利用ADAMS、HyPneu及MATLAB软件的协同仿真是准确描述机、电、液系统特性的一条有效路径。

基于CFD的仿生水动力学数值计算方法及其验证

鱼类经过长期的进化与自然选择,有着优异的水中游动能力,鱼类借助尾鳍能够进行快速高效的定向游动和快速启动/机动,借助胸鳍能够进行前进、后退和灵活的转向。本文基于计算流体力学(CFD)方法,给出适用于求解鱼类尾鳍/胸鳍的刚性运动以及身体躯干的柔性运动的网格划分策略,对仿生尾鳍、仿生胸鳍和仿生鱼在均匀来流中的水动力性能以及仿生鱼在静水中的自主游动进行数值计算。结果表明:基于CFD方法,采用结构与非结构混合的网格划分策略,应用动网格方法能够对仿生鱼的各类鳍及身体躯干的刚性或柔性运动进行有效的模拟,通过与实验结果进行对比,验证了对水动力性能求解的有效性。数值计算方法和验证算例对仿生水动力学的研究具有一定的理论参考意义。

仿生水动力学研究进展综述

海洋鱼类经过数百万年的自然进化,获得了非凡的水动力性能,人类迄今为止研发的任何水下航行体尚难以超越。仿生已成为提高水下航行体水动力性能的重要技术途径。本文对仿生水动力学的研究进展进行了梳理,重点评述了仿生水动力学理论研究、仿生推进/操纵和仿生减阻三个方面的国内外研究现状和发展趋势,并对仿生水动力学研究亟需突破的瓶颈问题和技术路线给出了若干建议。

Characteristics of seal shell body's rubber ring with bionic dimpled surfaces of aerodynamic extinguishing cannon

To solve the problem of sealing between the barrel and the rubber ring of shell body during an launching process of aerodynamic extinguishing cannon, a rubber sealing model with bionic dimpled characteristics was established based on the theory of bionic dimpled drag reduction and the principle of rubber sealing. In condition that the bionic dimpled characteristic diameters were 1, 2, 3, 4, and 5 mm, respectively, by numerical simulation, the influence of the installing compression of the rubber sealing ring on its surface stress and deformation was analyzed, and sealing performance of the rubber ring with different diameters of bionic dimpled was studied. The results show that the deformation of rubber ring appears prominent nonlinear characteristics when compression is increased from 1.5 mm to 2.5 ram. When the compression is 2.5 mm, the equivalent compression stress on the sealing areas of both sides of the rubber seal is greater than the working pressure of aerodynamic extinguishing cannon, which could meet the sealing requirement and would not cause leakage. So the rubber sealing ring with bionic dimpled surface possesses a good sealing characteristic and has no negative effect on the sealing of shell body; When the compression is 2.5 mm, the larger equivalent stress on the edge of sealing ring and the more even stress distribution in the high pressure area are generated due to the smaller compressive stress on the bionic dimple areas, which lays a foundation for the drag reduction characteristics of the shell body＇s rubber ring with bionic dimpled surface.

EVOLVEMENT AND CONTROL OF VULNERABLE ECOLOGICAL REGION—A Case Study in Ongniud Banner and Aohan Banner,Inner Mongolia

The evolvement of a vulnerable ecological region is a dynamic process, which is affected by various factors. During the evolvement process, human activities have a decisive effect. The purpose of studying vulnerable ecological region is to control human economic activities and to develop a negative feedback modulation mechanism.This paper established a model of vulnerable ecological region's evolvement by considering four synthetic variables.These synthetic variables are ecological carrying capacity, ecological resilience, economic development intensity, and economic development velocity. Finally, Ongniud Banner and Aohan Banner in North China were taken as study cases to simulate the evolvement processes of vulnerable ecological regions under different conditions of economic development. The results show that human activities have an important influence on the evolvement trend of vulnerable ecological region.

浅析科拉尼的自然主义设计观及在其陶瓷设计中的运用

卢吉·科拉尼是20世纪提倡自然主义设计观的先驱。研究其设计观有利于摆脱功能主义束缚,创造更人性化、趣味化的产品,为未来的设计提供新的发展方向。通过分析其设计观的产生、发展、升华及在陶瓷设计中的运用,可总结出科拉尼自然主义设计观的内容与内涵。科拉尼的自然主义设计观是将空气动力学、仿生学、人机工程学、材料工艺技术等领域综合知识的有机结合,从而产生的人性化设计方法与理念。更是符合中国传统文化中"天人合一、崇尚自然"哲学思想的设计哲学。

Effects of Oxygen Transfer Limitation and Kinetic Control on Biomimetic Catalytic Oxidation of Toluene

Under oxygen transfer limitation and kinetic control, liquid-phase catalytic oxidation of toluene over metalloporphyrin was studied. An improved technique of measuring dissolved oxygen levels for gas-liquid reaction at the elevated temperature and pressure was used to take the sequential data in the oxidation of toluene catalyzed by metalloporphyrin. By this technique the corresponding control step of toluene oxidation could be obtained by varying reaction conditions. When the partial pressure of oxygen in the feed is lower than or equal to 0.070 MPa at463 K, the oxidation of toluene would be controlled by oxygen transfer, otherwise the reaction would be controlled by kinetics. The effects of both oxygen transfer and kinetic control on the toluene conversion and the selectivity of benzaldehyde and benzyl alcohol in biomimetic catalytic oxidation of toluene were systematically investigated.Three conclusions have been made from the experimental results. Firstly, under the oxygen transfer limitation the toluene conversion is lower than that under kinetic control at the same oxidation conditions. Secondly, under the oxygen transfer limitation the total selectivity of benzaldehyde and benzyl alcohol is lower than that under kinetic control with the same conversion of toluene. Finally, under the kinetics control the oxidation rate of toluene is zero-order with respect to oxygen. The experimental results are identical with the biomimetic catalytic mechanism of toluene oxidation over metalloporphyrins.

Computational Study on Interaction Between Swimming Fish and Drifting Vortices Behind the Cylinder

To predict the flow evolution of fish swimming problems,a flow solver based on the immersed boundary lattice Boltzmann method is developed.A flexible iterative algorithm based on the framework of implicit boundary force correction is used to save the computational cost and memory,and the momentum forcing is described by a simple direct force formula without complicated integral calculation when the velocity correction at the boundary node is determined.With the presented flow solver,the hydrodynamic interaction between the fish-induced dynamic stall vortices and the incoming vortices in unsteady flow is analyzed.Numerical simulation results unveil the mechanism of fish exploiting vortices to enhance their own hydrodynamic performances.The superior swimming performances originate from the relative movement between the“merged vortex”and the locomotion of the fishtail,which is controlled by the phase difference.Formation conditions of the“merged vortex”become the key factor for fish to exploit vortices to improve their swimming performance.We further discuss the effect of the principal components of locomotion.From the results,we conclude that lateral translation plays a crucial role in propulsion while body undulation in tandem with rotation and head motion reduce the locomotor cost.

Bionic jumping dynamics of the musculoskeletal leg mechanism for quadruped robots

As the pneumatic artificial muscle （PAM） has flexibility properties similar to biological muscle which is widely used in robotics as one kind of actuators, the bionic mechanism driven by PAMs be- comes a hot spot in robotics. In this paper, a kind of musculoskeletal leg mechanism driven by PAMs is presented, which has three joints driven by four PAMs. The jumping movement is divided into three phases. The forward and inverse kinematics of the leg mechanism in different jumping phases is derived. Considering the ground reaction force between feet and environment, the dynamic in different jumping phases is analyzed by Lagrange method, then the relationship between PAM driving force and the joints angular displacement, angular velocity, angular acceleration during one jumping cycle is obtained, which will lay a foundatiori for the jumping experiment of the musculo- skeletal lez mechanism.

A survey on fabrication,control,and hydrodynamic function of biomimetic robotic fish

Understanding and replicating the locomotion principles offish are fundamental in the development of artificial fishlike robotic systems,termed robotic fish.This paper has two objectives:(1) to review biological clues on biomechanics and hydrodynamic flow control offish swimming and(2) to summarize design and control methods for efficient and stable swimming in robotic fishes.Our review of state-of-the-art research and future-oriented new directions indicates that fish-inspired biology and engineering interact in mutually beneficial ways.This strong interaction offers an important insight into the design and control of novel fish-inspired robots that addresses the challenge of environmental uncertainty and competing objectives;in addition,it also facilitates refinement of biological knowledge and robotic strategies for effective and efficient swimming.

MODELING AND PARAMETER IDENTIFICATION FOR MULTISTAGE SIMULATION OF MICROBIAL BIOCONVERSION IN BATCH CULTURE

The bioconversion of glycerol to 1,3-propanediol is a complex bioprocess. The item of product inhibition in the equation of Specific rate of cell growth is overlapped in [L. Wang, J. X. Ye, E. M. Feng and Z. L. Xiu, An improved model for multistage simula- tion of glycerol fermentation in batch culture and its parameter identification, Nonlinear Anal. Hybrid Syst. 3（4） （2009） 455462]. Therefore, in this work, the specific rate of cell growth is modified by the mechanism of multistage simulation of microbial bioconversion and the previous time-dependent model is converted to the autonomous standard form. The properties of the solutions for the nonlinear dynamic system are discussed and the identifiability of the parameters is proved. Finally the feasible optimization algorithm is constructed to find the optimal parameters for the system. Numerical result shows that the improved model with identified parameters can describe the batch culture better, compared with the previous results.