滩涂修井机机动性能设计计算

详细论述了滩涂修井机的机动性能指标的计算过程 。

车载式空中交通管理系统关键技术研究

在地震或其他强烈自然灾害后,机场固定式空中交通管理系统可能遭受严重破坏,车载式空中交通管理系统能够帮助快速恢复灾后机场交通。文中通过雷达载车系统的机动性设计和可快速拼接撤收的碳纤维天线设计等方法将一次雷达、二次雷达、ADS-B和空管自动化设备集成在载车平台上,以满足系统的机动性要求。样机系统经过实验验证,其功能指标满足一般中小机场的应急需要,架设和撤收时间均可控制在4 h以内,为空中交通管理提供了一种车载式应急产品。

Robust simultaneous tracking and stabilization of wheeled mobile robots not satisfying nonholonomic constraint

A robust unified controller was proposed for wheeled mobile robots that do not satisfy the ideal rolling without slipping constraint.Practical trajectory tracking and posture stabilization were achieved in a unified framework.The design procedure was based on the transverse function method and Lyapunov redesign technique.The Lie group was also introduced in the design.The left-invariance property of the nominal model was firstly explored with respect to the standard group operation of the Lie group SE(2).Then,a bounded transverse function was constructed,by which a corresponding smooth embedded submanifold was defined.With the aid of the group operation,a smooth control law was designed,which fulfills practical tracking/stabilization of the nominal system.An additional component was finally constructed to robustify the nominal control law with respect to the slipping disturbance by using the Lyapunov redesign technique.The design procedure can be easily extended to the robot system suffered from general unknown but bounded disturbances.Simulations were provided to demonstrate the effectiveness of the robust unified controller.

Research on steel-fibber polymer concrete machine tool structure

Researched on the design and manufacturing of machine tool bed made by Steel-fibber Polymer Concrete(SFPC),which analyzed the static,dynamic and thermal performances of the bed.The results of study prove that machine tool bed made with SFPC is much more superiority than made in cast iron in dynamic and thermal perform- ances,and is more superiority then made in Polymer Concrete (PC) in static perform- ances.It can be concluded that the static,dynamic and thermal properties of machine tool can be improved by manufacturing machine tool bed with SFPC.Also SFPC machine tool bed posses some other advantages in the following: short development time,simple pro- duction process,reducing cost cost,saving energy,iron and steel.

Vibration-based feature extraction of determining dynamic characteristic for engine block low vibration design

In order to maintain vibration performances within the limits of the design, a vibration-based feature extraction method for dynamic characteristic using empirical mode decomposition （EMD） and wavelet analysis was proposed. The proposed method was verified experimentally and numerically by implementing the scheme on engine block. In the implementation process, the following steps were identified to be important： 1） EMD technique in order to solve the feature extraction of vibration signals; 2） Vibration measurement for the purpose of confirming the structural weak regions of engine block in experiment; 3） Finite element modeling for the purpose of determining dynamic characteristic in time region and frequency region to affirm the comparability of response character corresponding to improvement schemes; 4） Adopting a feature index oflMF for structural improvement based on EMD and wavelet analysis. The obtained results show that IMF of signal is more sensitive to response character corresponding to improvement schemes. Finally, examination of the results confirms that the proposed vibration-based feature extraction method is very robust, and focuses on the relative merits of modification and full-scale structural optimization of engine, together with the creation of new low-vibration designs.

A Study on the Individual Distance of a Small RobotMoving towards Adult Male and Female

In Japan, robots are a regular feature of daily life and in rehabilitation support care and reporting on any emergencies involving the elderly. This study is on design guidelines for the living space with robots and can be applied to the architectural planning and focused on the basic environmental primary factor. The key terms were space, people-adult male and female, positions, and the robot-size, speed-settings and approaching angles. This research is the distances a small mobile robot moves to an adult male compared with that toward an adult female. The authors focus on a small mobile robot and identify the distances from which the robot can approach individuals, and also clarify how the distances to individuals change as the robot＇s speed and angle of approach varies. The study did this experiment to analyze 30 patterns per person and also when at an angle of the difference of male and female, two position standing/seated and three speed-settings0.08 m/sec, 0.24 m/sec and 0.48 m/sec and five directions--0°, 45°, 90°, 135° and 180°.

Transient reliability optimization for turbine disk radial deformation

The radial deformation design of turbine disk seriously influences the control of gas turbine high pressure turbine(HPT) blade-tip radial running clearance(BTRRC). To improve the design of BTRRC under continuous operation, the nonlinear dynamic reliability optimization of disk radial deformation was implemented based on extremum response surface method(ERSM), including ERSM-based quadratic function(QF-ERSM) and ERSM-based support vector machine of regression(SR-ERSM). The mathematical models of the two methods were established and the framework of reliability-based dynamic design optimization was developed. The numerical experiments demonstrate that the proposed optimization methods have the promising potential in reducing additional design samples and improving computational efficiency with acceptable precision, in which the SR-ERSM emerges more obviously. Through the case study, we find that disk radial deformation is reduced by about 6.5×10–5 m; δ=1.31×10–3 m is optimal for turbine disk radial deformation design and the proposed methods are verified again. The presented efforts provide an effective optimization method for the nonlinear transient design of motion structures for further research, and enrich mechanical reliability design theory.

Experimental Study on Friction Characteristics of Caragana korshinskii Kom

Caragana korshinskii Kom, which is a kind of excellent shrubs, has strong resistance to windstorms, and it is also a kind of forage that is of high nutritional value as well as a forming fuel conversion resource that is of high caloric. Caragana korshinskii Kom is of high lignifications after growing for a few years and the toughness of it is considerably high. Currently in China, equipments of harvesting and processing for ripe crops can hardly finish the mechanized production for Caragana korshinskii Kom. Friction characteristics of woody material for Caragana korshinskii Kom under different conditions should be given when the relevant operation machinery is designed, which can provide physical parameters for transportation of Caragana korshinskii Kom as well as the designing of relevant machinery. The paper bases on the research of friction characteristics between Caragana korshinskii Kom whose diameter of 7, 10, and 13 mm under sampling directions of 0°, 45°,and 90° and machinery materials that are commonly used such as steel plate, rubber sheet and so on, and meanwhile the test considers factors such as different conditions of Caragana korshinskii Kom, different materials of machines, different angles and so on. The data strongly suggests that the average static, dynamic friction coefficient between Caragana korshinskii Kom and steel plate is 0.399 711 and0.353 022, respectively; The average static and dynamic friction coefficient between Caragana korshinskii Kom and rubber sheet is 0.965 178 and 0.883 667, respectively. The maximum of static and dynamic friction coefficients is when the angle between the direction of sampling and the direction of movement is vertical. As the angle increased, the dynamic and static friction coefficient decreased. The friction coefficient between Caragana korshinskii Kom and steel plate were increased with the increase of the diameter of Caragana korshinskii Kom, but the diameter have no effect on the dynamic friction coefficient between Caragana korshinskii Kom and rubber plate. The conclusion of this paper can provide references for research on machines that are relevant to transportation and particle forming of Caragana korshinskii Kom.

Studies on the influence of spar position on aeroelastic optimization of a large aircraft wing

Aeroelastic problems are encountered at the preliminary design stage of flexible wings for large aircraft. A three-dimensional finite element model of a high-aspect-ratio wing was built, and the influence of the front and rear spar positions on the results of the aeroelastic analysis and optimization was studied to improve the wing structure desgin. The most feasible and optimal solutions were effectively obtained by aeroelastic optimization. In particular, the position parameter of the front spar has a greater influence on the aeroelastic analysis and optimization than the rear spar. In addition, some key constraints became re- strictive leading to a rapid increase in the structural weight. Therefore, reasonable constraints were necessary for the optimization of results.

Skin friction reduction characteristics of variable ovoid non-smooth surfaces

The use of bionic non-smooth surfaces is a popular approach for saving energy because of their drag reduction property. Conventional non-smooth structures include riblets and dimples. Inspired by sand dunes, a novel variable ovoid non-smooth structure is proposed in this study. The body of the variable ovoid dimple was designed based on three size parameters, the radius, semimajor, and depth, and a 3D model was created based on UG software. The constructed variable dimples were placed in a rectangular array on the bottom of a square tube model. Following ANSYS meshing, the grid model was imported into FLUENT, where the flow characteristics were calculated. Results of skin friction reduction were achieved and the effect of the design parameters on different variable ovoid dimples was obtained by orthogonal testing. Various aspects of the skin friction reduction mechanism were discussed including the distribution of velocity vectors, variation in boundary layer thickness, and pressure distribution.

Design and performance test of a two-axis fast steering mirror driven by piezoelectric actuators

A novel design of a two-axis fast steering mirror(FSM) with piezoelectric actuators is proposed for incoherent laser beam combination. The mechanical performance of the FSM is tested. The results show that the tilting range of the mirror is about 4 mrad, and the 1st-order resonance frequency is about 250 Hz. A self-designed grating encoder is taken as the sensor, which ensures the optimal precision of 10 μrad. The novel mechanical design can meet the requirement of engineering in incoherent laser beam combination.

Aerodynamic/mechanism optimization of a variable camber Fowler flap for general aviation aircraft

A conventional Fowler flap is designed to improve the take-off and landing performances of an aircraft. Because the flight states of general aviation aircraft vary significantly. A Fowler flap with a double-sliding track has been designed, which is ca- pable of changing airfoil camber while cruising and climbing as well as meeting low-speed performance requirements. The aerodynamic characteristics of the variable camber Fowler flap were studied by computational simulation, and cambering was found to be beneficial for improving the lift-to-drag ratio when the lift coefficient was larger than the critical value, below which decambering was more effective; this critical value differed somewhat under different conditions. Taking the mecha- nism into account, the take-off and landing configurations were optimized on the basis of the GA （W）-1 airfoil with a 30% chord Fowler flap. Compared with reference configuration, the maximum lift coefficient of optimized take-off configuration was increased by 6.6% as well as the stalling angle and the lift-to-drag ratio were increased by 1.3° and 7.58%, respectively. Moreover, the maximum lift coefficient of the optimized landing configuration was increased by 6.3%, and the stalling angle was increased by 1.1°; however, the nose-down pitching moment of both configurations increased. Similar results were at- rained on a general aviation aircraft wing/body combination nism was established in a computer-aided design system, achieved by the double-sliding track. A 3D model of the variable-camber Fowler flap driving mecha- and the results showed that all design configurations could be

The influence of rolling bearing clearances on diagnostic signatures based on a numerical simulation and experimental evaluation

This paper presents investigations into the influences of bearing clearances on the diagnostic features of monitoring rolling-bearings. A nonlinear dynamic model of a deep groove ball bearing with five degrees of freedom is developed for numerical analysis under increased radial clearances which are due to not only the scenarios of bearing grades but also gradual wear with bearing service lifetime. The model incorporates local defects and clearance increments in order to gain the insight into the bearing dynamics under different fault cases along with clearance changes. Numerical results show that the vibrations at fault characteristic frequencies exhibit clear inconsistency with common understandings for different cases of increased clearances. This study highlights that it has to take into account the clearance effect, especially for the inner race fault, in order to avoid the under-estimate of fault sizes which may be indicated by the feature amplitude reduction.

VirtMan:design and implementation of a fast booting system for homogeneous virtual machines in iVCE

Internet-based virtual computing environment （iVCE） has been proposed to combine data centers and other kinds of computing resources on the Internet to provide efficient and economical services. Virtual machines （VMs） have been widely used in iVCE to isolate different users/jobs and ensure trustworthiness, but traditionally VMs require a long period of time for booting, which cannot meet the requirement of iVCE＇s large-scale and highly dynamic applications. To address this problem, in this paper we design and implement VirtMan, a fast booting system for a large number of virtual machines in iVCE. VirtMan uses the Linux Small Computer System Interface （SCSI） target to remotely mount to the source image in a scalable hierarchy, and leverages the homogeneity of a set of VMs to transfer only necessary image data at runtime. We have implemented VirtMan both as a standalone system and for OpenStack. In our 100-server testbed, VirtMan boots up 1000 VMs （with a 15 CB image of Windows Server 2008） on 100 physical servers in less than 120 s, which is three orders of magnitude lower than current public clouds.