Investigation of knitted fabrics and the deformation of their assemblies by the Y-shaped specimen method

Textile fabric deformability during garment wear is a very important property as it influences performance conditions, the wearer’s comfort and the aesthetic view of the garment. Deformation of material in the garment depends on the clothing construction, anatomical features and physical activity of the wearer and garment fit. This paper presents an investigation of knitted fabrics and the deformation of their assembly peculiarities, considering the complex behavior of textile materials during wear using the Y-shaped specimen method. The fabric element partially experienced force affects in respective garment areas. In this case, several deformation types appear at the same type. In our research the special shaped specimen of form “Y” was used to performing the uniaxial tensile test to simulate this phenomenon. According to this method, longitudinal, transversal and angular characteristics describing the deformation of textile materials and their stitched systems were determined. It was found that after the extension indicator of angular deformation has changed the most, the amount of change reached up to 70%. In the Y-shaped knitted specimens, the seam significantly influences the size of the tensile force. Also, the changes of angle indicator, when the specimens are joined with seams, are obvious and reach 50%.

A Hybrid PSO-PI Controller for the LEO Satellite Tracking System

This paper presents a smart-routing mechanism of a control system to track Low Earth Orbit (LEO) satellites. Satellite tracking mainly relies on the antenna pointing database generated by SGP4 orbit forecasting model and follow the point coordinates to command the rotation of the axes. Gears rotation gaps will affect the strength of the received signal; the Proportional Integral (PI) controller is used to adjust the error values caused by the drive shaft mechanism. Particle swarm optimization (PSO) algorithm has fewer parameter settings and the advantages of fast convergence, which is adopted for variable selection and optimization for the parameters kp and ki of PI controller. The resolver feedback mechanism of actual angle indicator is using as a basis for performance adjustment in the search process. The experimental results of a three axes tracking system demonstrate the reliability and better performance of the proposed PSO-PI satellite tracking system.

The Course Angle Indicator Based on Magnetic Resistance Sensor

A kind of digital compass based on magnetic resistance sensor was designed. The principle of the course angle measurement based on magnetic resistance sensor was analyzed, and it elaborates the scheme of course angle system design and implementation. FPGA was chosen as processor, and the embedded kernel was built up based on SOPC. The course angle measurement and digital display were realized. The error compensation was used in this system. The error analysis and contrast were given. This kind of course angle indicator is small volume and high precision. It can be applied to different carrier, and has high universality and practical value.