基于“虚拟样机”技术交流接触器的磁系统参数优化

在三维有限元分析基础上 ,进行二次开发 ,利用ANSYS的寻优功能 ,分析交流接触器操作电磁铁的静态特性 ,并准确计算其吸力特性F =f(δ)。在此基础上 ,利用“虚拟样机”技术 ,对影响接触器磁系统性能的参数设计提出优化方案。最后比较了改进前、后样机的静态特性。

Kinematics simulation and application for machine tool based on multi-body system theory

Based on the multi-body kinematics principle, the topological structure and restriction relation among parts of machine tool and 3D multi-body model are constructed, the kinematics simulation system of machine tool is developed. The designer can observe the movement and machining course of the whole machine tool and understand accurately the kinematics parameters of components such as position, velocity and acceleration. Also the designer can estimate the pose of components in the virtual circumstance and forecast accurately and correct problems which may appear during the design before the prototype is manufactured to assure the feasibility of design scheme, shorten period of product design and reduce product cost. The simulation system is used during the design of CK1416 high speed and precision numerical control lathe. The curves of ball screw angular velocity and carriage displacement agree well with the results of theoretical calculation and the constructed model is correct.

DESIGN OF NEW PASSIVE ADAPTIVE SHOCK ABSORBER OF LANDING GEAR AND STUDY OF ITS LANDING PERFORMANCE

A new passive adaptive shock absorber of the landing gear with double-cavity and dual-damping is studied. Its mathematical model and the virtual prototype are established based on the dynamics simulation software ADAMS. The landing dynamic characteristics and the effect of the parameters on the proposed adaptive shock absorber are analyzed. The results show that the proposed adaptive shock absorber has the slightly better landing performance at the normal load case and much less overload at the crudely landing case than the shock absorber with single-cavity and variable orifice. It also can be concluded that the overload of the proposed adaptive shock absorber can be reduced through increasing the volumes of both cavities or decreasing the pressure of the high pressure cavity or increasing the pressure of the low pressure cavity.

Modeling and simulation of ocean mining subsystem based on virtual prototyping technology

According to the virtual prototyping technology and the theory of dynamics of multi-rigid-body system, a virtual prototyping of ocean mining vehicle was constructed by using 3-dimensional entity modeling software ((Pro/E),) automatic dynamic analysis of mechanical systems(ADAMS) and advanced visual software(AVS). After 32 new modules were developed with C++ at AVS platform, the interface problems of the 3 types of software were solved effectively and a visual environment for ocean mining subsystem was constructed. Based on the similarity (theory) and similarity experiments, the validity and reliability of the virtual prototyping were verified. By using the (constructed) virtual prototyping, the relevant parameters, such as cutting depth, rotation speed of roller,marching speed of mining vehicle can be adjusted one by one. After repeatable virtual tests and analysis its corresponding dynamic characteristics, the structure parameter of mining vehicle and the parameter of mining process can be optimized fast and accurately. The experiment and simulation results show that, under the controlled mining parameters, 4 function expressions between the average force of single pick,average torque,average cutting power,energy consumption ratio and cutting depth are obtained. The maximum force of a single pick is less than (11090N) and the maximum torque of the roller is less than 3600N·m.

Path-tracking Control of a Tractor-aircraft System

An aircraft tractor plays a significant role as a kind of important marine transport and support equipment. It＇s necessary to study its controlling and manoeuvring stability to improve operation efficiency. A virtual prototyping model of the tractor-aircraft system based on Lagrange＇s equation of the first kind with Lagrange mutipliers was established in this paper, According to the towing characteristics, a path-tracking controller using fuzzy logic theory was designed. Direction control herein was carried out through a compensatory tracking approach. Interactive co-simulation was performed to validate the path-tracking behavior in closed-loop, Simulation results indicated that the tractor followed the reference courses precisely on a flat ground.

Dynamic Response of Functional Virtual Prototyping of Motorcycle under Combined Excitations

This paper developed 3D product models of motorcycle and engine by UGNX as well as virtual prototyping by ADAMS program with road roughness generated by MATLAB. Under the straight-line running condition, the dynamic responses of motorcycle multibody system to both road and engine excitations were compared with those to only road excitation in terms of vertical acceleration response, amplitude frequency response and power spectral density. The comparisons of simulation data showed that the response due to flat road excitation was around 20 Hz, while that to the combined excitations was in a wide frequency band, of which the major components focused on 10 Hz, 15 Hz, 35 Hz ,70 Hz, 100 Hz and even higher frequencies, reflecting the characteristics of engine excitation based on its unbalanced inertia force and torque. It is concluded that the high fidelity virtual prototyping can simulate the dynamics of motorcycle product well in investigating the vibration and ride comfort performance.

Study on co-simulation model of forging manipulator based on virtual prototyping

Based on the characteristics of integrated virtual prototype technology, the mechanical system sub-model, the hydraulic system sub-model and the control system sub-model of a forging manipula- tor system have been built using a variety of software, and a forging manipulator mtrltidisciplinary co- simulation model has been also built using a method of simulation models interface. Then the simu- lation and experiment are finished, and the result of the experiment is in good agreement with the re- sult of the simulation. It shows that the co-simulation model established can simulate accurately pa- rameter changes in real time during the moving of the forging manipulator such as displacement, ve- locity and pressure flow, which is of important significance for the optimized design of the forging manipulator system to establish the models.

Global optimization for ducted coaxial-rotors aircraft based on Kriging model and improved particle swarm optimization algorithm

To improve the operational efficiency of global optimization in engineering, Kriging model was established to simplify the mathematical model for calculations. Ducted coaxial-rotors aircraft was taken as an example and Fluent software was applied to the virtual prototype simulations. Through simulation sample points, the total lift of the ducted coaxial-rotors aircraft was obtained. The Kriging model was then constructed, and the function was fitted. Improved particle swarm optimization(PSO) was also utilized for the global optimization of the Kriging model of the ducted coaxial-rotors aircraft for the determination of optimized global coordinates. Finally, the optimized results were simulated by Fluent. The results show that the Kriging model and the improved PSO algorithm significantly improve the lift performance of ducted coaxial-rotors aircraft and computer operational efficiency.

Operator health risk evaluation of off-highway dump truck under shovel loading condition

To evaluate the operator health risk exposed to whole-body vibration(WBV) while the electric-shovel loads the ore on the truck body, the semi-truck mathematical model and 3-D virtual prototype were built to simulate the high shockwave of truck cab under the shovel loading. Discrete element method was utilized to accurately estimate the impacting force on the truck body. Based on the ISO 2631-5 criteria, the Sed is about 0.56 MPa in both models, which means that the dump operators have a high probability of adverse health effects over long-term exposure to these vibrations. The 4-DOF operator model was built to investigate the biodynamic response of seated-human body exposed to WBV in terms of the transmission of vibrations through the body. The results show that the response peak is in the frequency range of 4-6 Hz corresponding to the primary body resonant frequency.

新工科背景下“虚拟样机技术”项目化教学研究

“虚拟样机技术”是现代设计方法的重要分支,传统教学方法包括课堂讲解以及上机操作两个环节,教学案例简单、陈旧、缺乏系统设计,教学效果欠佳,不能适应新工科对人才培养的要求。针对上述问题,提出新工科背景下“虚拟样机技术”项目化教学,结合自身科研、学生课程实践,以项目化方式重新规划教学内容、教学方法和考核方式,通过精心设计新颖、系统化、连贯性项目,使学生由浅入深、循序渐进掌握“虚拟样机技术”,以满足我校新工科背景下人才培养要求。

Study on conditions of internally carried air-launched launch vehicles based on the virtual prototype technology

A method based on the virtual prototype technology simulating the separation of a launch vehicle from its aircraft in the aircraft wake was proposed based on the internally carried air-launched launch vehicle program.In this method,the full-scale model of the aircraft,the vehicle and the parachute are constructed.Then,they are imported into the ADAMS software,constraint solutions and driving forces are then added for visual dynamic simulation.The unsteady aerodynamic forces of the vehicle in the aircraft wake are calculated by CFD and the moving grid technique.The forces generated by the parachute can be derived from the Kirchhoff motion equation.Through comparing and analyzing the simulation results under different launch conditions,it has been proven that this method simulates the separation of a launch vehicle from the aircraft in the aircraft wake accurately.It provides the foundation for the aggregate project of internally carried air-launch vehicles,and offers a new referenced method for multi-body dynamic simulation.

Research of MMW radiometer virtual prototyping technology

The idea of millimeter-wave (MMW) radiometer virtual prototyping is discussed in this paper. Designing environment, designing method and the main modeling components of virtual MMW radiometer are researched. Important external parameters, which have significant influence to composing system, are used to components modeling, and then components are taken to buildup virtual MMW radiometer system. Moreover, the effect to output is contrasted whether there is a low-noise amplifier or not.

Optimization of the Tracking Mechanism for a PV String

The paper presents researches on increasing the energetic ＆ economic efficiency of the photovoltaic （PV） conversion by designing and optimizing a dual-axis tracking mechanism that simultaneously changes the position of the modules using two motor sources. The driving source for the daily motion is a rotary motor, while the elevation motion is performed with a linear actuator. The main task in optimizing the tracking mechanism is to maximize the energetic gain by increasing the solar input and minimizing the energy consumption for tracking. The design strategy aims to identify the optimum angular field for the daily motion, as well as the optimum actuating time in the step-by-step motion. The study is made by developing the virtual prototype of the tracking mechanism, in the mechatronic concept. The virtual prototyping platform includes the following software solutions： CATIA （Computer Aided Tri-Dimensional Interface Application）--to create the solid model, which contains information about the mass ＆ inertia properties of the parts, ADAMS （Automatic Dynamic Analysis of Mechanical Systems）/View--to model the mechanical structure of the solar tracker, and EASY5 ＆ ADAMS/Controls-for the control system design.

A leveling mechanism for the platform based on booms-constraint control of aerial vehicle

In order to achieve an automatic leveling function for work platforms of aerial vehicles with mixed-booms( MAV) in full elevating domain,an auto-leveling mechanism for the platform is proposed based on a control method of booms-constraint,where mixed-boom structures and elevating characteristics are considered. Three models of constraint strategies include non-constraint model,elevating constraint model and lowering constraint model,which is designed to meet the leveling requirements in full working extent. Through the hydro-mechatronic unified modeling,a virtual prototype model is set up based on the auto-leveling mechanism,and leveling performances of the platform are studied during booms elevating to the maximum working height and extent. Simulation results show that the control method of booms-constraint can realize auto-leveling of the platform under two typical working conditions,meanwhile a leveling deviation appears at the constrained point,but the platform inclination is adjusted in the permissible range. The control method does not only restrict booms' freedom elevating to a certain extent,but also impacts the booms extending to the maximum working range. Experimental results verify that the auto-leveling mechanism based on booms-constraint control is valid and rational,which provides an effective technology approach for development of the platform leveling of MAV.

Dynamic simulation of hydrokinetic hammer based on virtual prototyping technology

This study presented the specified steps of comprehensively analyzing the hydraulic-driven hammer system with the application of the Virtual Prototype Technology.By comparing the simulation results with experimental phenomena and data,the correctness of simulation analysis conclusion is verified.Meanwhile,by means of its perfect visualization,the internal work process which can not be seen before is simulated.The mechanism of some abnormal phenomena encountered during the experiment is explained.

Advances in Virtual Prototyping Techniques for Design of Compact Cyclotrons

As a novel technique in engineering,Virtual Prototyping(VP)was applied to the design of cyclotrons with the purpose of shortening the development period and reducing the costs for physical prototypes.The advances in VP techniques for compact cyclotron design in HUST are introduced.The idea of multi-domain collaborative design was proposed.This paper describes the pythonic mixed language programming approach to develop the VP integrate platform.Under this platform,the optimization design of main magnet,RF cavity and central region of cyclotrons is to be achieved.

Rigid-Flex Coupling Modeling and Simulation on Multistage Gear Transmission System

As multistage gear transmission systems are complex and precise, the flexibility of shaft can influence the dynamic response of system. In order to study dynamic response of the system, we build the rigid model of gear system and the finite element model of the gear shaft. virtual prototype technology, and a contrast between rigid The rigid-flex coupling model is established with the model and rigid-flex coupling model is constructed. With these methods, the dynamic responses with different rotation speeds and different loading magnitudes are examined. We also analyze the influence of shaft flexibility, rotation speeds and loading magnitudes on the vibration characteristics of gear transmission systems.