Spatial interpolation of point velocities in stream cross-section

The most frequently used instrument for measuring velocity distribution in the cross-section of small rivers is the propeller-type current meter. Output of measuring using this instrument is point data of a tiny bulk. Spatial interpolation of measured data should produce a dense velocity profile, which is not available from the measuring itself. This paper describes the preparation of interpolation models. Measuring campaign was realized to obtain operational data. It took place on real streams with different velocity distributions. Seven data sets were obtained from four cross-sections varying in the number of measuring points, 24-82. Following methods of interpolation of the data were used in the same context: methods of geometric interpolation arithmetic mean and inverse distance weighted, the method of fitting the trend to the data thin-plate spline and the geostatistical method of ordinary kriging. Calibration of interpolation models carried out in the computational program Scilab is presented. The models were tested with error criteria by cross-validation. Ordinary kriging was proposed to be the most suitable interpolation method, giving the lowest values of used error criteria among the rest of the interpolation methods.

Study on Interpolation Arithmetic of Tube Bender with Four-Axis CNC System for Spiral Fluorescent Lamp

Taking tube bender system for producing pagoda-shaped fluorescent tubes as an example in this paper, four coordinates movement equations of CNC system with Parabolic characteristic are derived and an algorithm for nonlinear interpolation of four-axis linkage based on target point tracking algorithm is presented for the spiral fluorescent tube bending machine with CNC system by means of deep analysis of the pulse interval interpolation algorithm. By using this algorithm, coordinated control of four coordinates in tube bender system can be realized and, in addition, software programming procedure can be directly used for this system. Test shows that the system which uses this interpolation method has the characteristic of simple operation, high speed and high single-pulse interpolation accuracy.

Optimization of Structural Parameter of Shape-Adaptive Tool for Compliant Polishing of Aspheric Parts

The tool position based on the general interpolation arithmetic will make sharp changes which bring a harmful influence to the mixed control of pose and position as well as the normal force in grinding process. In this paper, a new type of shape-adaptive tool is proposed for the common NC lathe. The effective of shape-adaptive and the stability of polishing force is studied utilizing the dynamic analysis software ADAMS, at the same time, the structural is optimized. The simulation outcome indicates that the tool could both adapt to the surface of workpiece and remove the influence brought by interpolation arithmetic.