Applied Mechanics and Materials Vols. 190-191

Abstract: Abstract: For the purpose of scene simulation of satellite moving on track and shaded part compute for solar panel, this paper analyzed the visualization system's software architecture, introduced Program design method with GDI+ and OpenGL on MFC frame. Based on the analysis, software architecture was optimized and some reusable classes were also designed. Therefore a more reusable, extendable and modularized visualization system can be realized. It covered a wide range of function such as the visual simulation, shaded part compute for solar panel and results display. The results showed that this visualization system was satisfactory and feasible in the simulation.

Abstract: Some satellites employ payloads with rotating parts of which the motion degrades satellite stability and pointing accuracy. In this paper, to satisfy satellite attitude requirement, a system using two compensation wheels to counteract space turntable momentum is presented, which adopts mechatronics design and considers the inertia property variation of rotating part. A double closed loop controller is introduced for this compensation system. The system analysis and simulation are given, and the simulation results reveal this system has a satisfied performance.

Abstract: Abstract: Aiming at transfer alignment of gimbaled INS(Inertial Navigation Systems) on moving base, the paper proposes an attitude matching alignment model to calibrate the slave platform. This method is achieved by applying a Kalman filter, which based on the frame angle error equations, to estimate the fixed misalignment angle and obtain the misalignment angle. Firstly, the frame dynamics equations are introduced and the relation between the fixed angle and misalignment angle is discussed. Secondly, the frame angular error differential equations are built up via the frame angle information from the master and the slave INS platform. Lastly, the attitude matching alignment model is designed based on Kalman filter technology. The simulation results show that the proposed method can obtain an alignment accuracy of 40", and the corresponding alignment time is 30 seconds.

Abstract: In this paper, we design the open numerical control system of PC based on embedded motion control card. This open NC teaching machine tool is not only for the removal to meet the teaching requirements of the mechanical design, but also allows users to define instructions, to convert CNC instructions to the control card built-in function on the PC; to export the control information to control machine tool axis movement. This greatly enhances the students’ interest, and helps them to faster formation of the core competencies of the CNC technology.

Abstract: Feature extraction is an important phase in SAR imagery interpretation and target recognition, electromagnetic scattering characteristic is the inherent characteristic of target on SAR imagery. High resolution SAR imagery interpretation and target recognition, particularly the ground vehicles recognition, needs to be carried through based on target scattering characteristic and target’s electromagnetic feature extraction. This paper analyzes the electromagnetic scattering mechanism of typical ground vehicles firstly, and the feasibility of modeling the electromagnetic scattering characteristic of ground vehicles with attributed scattering center model has been discussed in brief. And then, by making some improvement on the existing method of attributed scattering center feature extraction from SAR imagery, a modified method for feature extraction of ground vehicles from measured high resolution SAR imagery based on electromagnetic scattering characteristic has been proposed. Finally, performance of the proposed algorithm has been validated on measured 0.3m resolution MSTAR and 0.1m resolution MiniSAR SAR imagery data.

Abstract: A whole design scheme of distributed remote monitoring system of NC machine tools is put forward and the middleware technology of combination of CORBA and web service is importantly discussed in this paper.This system is divided into three layers—field layer,middle layer and user layer. Finally, in this system platform, the errors of circular interpolation and linear interpolation are measured.

Abstract: The steering frequent problems in the five-axis NC machining tool path planning based on space-filling curve method was researched, then a double spiral space-filling curve was proposed. Owing to frequently reverse, it was adopted that an arc on transition instead of the right angle, so the impact in tool and the part in machining process was reduced. Combined with the free surface, the plane filling curve with the surface parameters corresponding to the mapping on the surface thereby generated the idea of machining tool paths. Finally, the method was used for a specific surface, and the effectiveness of the method was verified.

Abstract: A variational method using the principle of virtual work (PVW) is presented to formulate the problem of the microcantilever stiction. Compared with the Rayleigh–Ritz method using the arc-shaped or S-shaped deflection, which prescribes the boundary conditions and thus the deflection shape of a stuck cantilever beam, the new method uses the matching conditions and constraint condition derived from PVW and minimization of the system free energy to describe the boundary conditions at the contact separation point. The transition of the beam deflection from an arc-shape-like one to an S-shape-like one with the increase of the beam length is shown by the new model. The (real) beam deflection given by this new model deviates more or less from either an arc-shape or an S-shape, which has significant impact on the interpretation of experimental data. The arc-shaped or S-shaped deflection assumption ignores the beam bending energy inside the contact area and the elastic energy due to the beam/substrate contact, which is inappropriate as shown by this study. Furthermore, the arc-shaped or S-shaped deflection only approximately describes the deflection shape of a stuck beam with zero external load and obviously, the external load changes the beam deflection. The Rayleigh–Ritz method using the arc-shaped or S-shaped deflection assumption in essence can only be used to tell approximately whether stiction occurs or not. Rather than assuming a certain deflection shape and by incorporating the external load, the new method offers a more general and accurate study not only on the microcantilever beam stiction but also on its de-adherence.

Abstract: Probe characteristics are important for eddy current displacement sensors. Probes made by multilayer printed circuit board (PCB) are good at maintaining quality consistency and their axial length was short. As design principles for wired probes were not suitable for PCB probes, an analysis and design method for them was developed. In this paper, PCB probe characteristics were first analyzed with 3D eddy current field FEM software. The process was time-consuming. To increase analysis efficiency, a simplified 2D axial symmetry model was used to replace the 3D model. The analysis results were compared and their difference was small. The probe resister and inductance were compared with measurement result of a test PCB probe and they agreed well. Based on 2D model, a series of analysis was performed and basic design principles for PCB probes were obtained. Based on the principles, a new PCB probe with better performance was designed.

Abstract: Based on the fuzzy method, a PC-based precision force control scheme is proposed for the electro-hydraulic servo press system. The main feature of proposed scheme is to develop a composite control of relief valve and flow servo valve. With the feedback of force sensor, the fuzzy-based control system is realized by LabVIEW for achieving the precision force control of hydraulic cylinder. In the experiments, a practical platform of hydraulic servo press system is used to demonstrate the effectiveness of proposed scheme. The testing results indicate the accurate output responses.