Improved Control of Radiator Heating Systems with Thermostatic Radiator Valves without Pre-Setting Function

Low-temperature district heating will play an important role in a future free of fossil fuels. This will only be able to be realized through the low-temperature operation of heating systems in existing buildings. Existing radiator systems can operate with low temperatures for most of the year because they are designed for extremely cold days, but errors have to be corrected and the control of the radiator systems needs to be improved. In this paper, we present a strategy to achieve low-temperature operation from the radiator system of a multi-family building in Denmark without a pre-setting function in the thermostatic radiator valves. The strategy is based on operating the system with a combination of a minimum supply temperature and small temperature differences over the radiators. The operation of the system is analyzed through a thermal-hydraulic model. A minimum supply temperature weather compensation curve was calculated and implemented in the central supply temperature control. Return temperature measurements in the substation, the risers, and several critical radiators were performed before and after the implementation of the strategy. The measurements confirm that a lower supply temperature results in a reduction of the return temperature. However, the system operator needs to be supported by a tool package to correctly maintain the system’s operation.

Mechanical Analysis of Crossbeam in a Gantry Machine Tool and its Deformation Compensation

The beam is an important component in agantry machining center, and its deformation is believed to have asignificant impact on both the machining accuracy and the machining performance. In this research, the finite element models of a complete gantry machining center and the crossbeam are established, in whicht he restraint and boundary conditions for the finite element analysis are also introduced. It is noted thatthe impact of balance cylinders on the key components is fully considered when dealing with the force analysis. Computed results of the static characteristic analysis showed that the maximum deformation is about 0.080925 mm when crossbeam operates under different conditions. Then, the distortion curve and the compensation curve of guide rail are obtained, and the equation of a fitting compensation curve is also deduced through numerical analysis. This research is expected to provide a theoretical guide for distortion compensation of the crossbeam.

Applied Research of Cloud Computing in the Tool Radius Compensation Discrimination of Numerical Control Programming

The cloud computing can allocate computer resources according to customers different demand dynamic status, which has improved the calculation efficiency, and saved the cost of hardware. This paper establishes the 3D mathematical model of data programming tool radius compensation system, and gets the tool radius compensation control equation according to the interpolation function. It designs the tool radius compensation discrimination system with the combination of UG software. In order to verify the validity and reliability of the system, the paper takes the processing process of leaf as an example to design the tool radius compensation algorithm, and the compensation deviation has been made numerical simulation, which has obtained error compensation curve and tool radius compensation parameter table. It can obtain reasonable tool compensation cutter and cycle according to the input of tool parameters, which provides technical support for the research of numerical control (NC) machining technology.

Research on Dot Gain Compensation Curve Algorithm Model

To make the dot gain compensation curve more precise, this paper analyzes the methods already used and then propose a new method. We implement this new method and the old ones respectively through MATLAB, and get their dot gain compensation curves. At the same time, the average error and variance were counted to test their precision. The results show that the new method can apparently improve the precision and reduce the error. The average error of the normal method is 2.96% while it is reduce to 1.56% by the new method.

DETECTION AND COMPENSATION ALGORITHM FOR BACKLIGHT IMAGES WITH FUZZY LOGIC AND ADAPTIVE COMPENSATION CURVE

This paper presents a new algorithm for detection and compensation of backlight images. The proposed technique attacks the weakness of the conventional backlight image processing methods such as over-saturation, losing contrast and so on. The proposed algorithm consists of two operation phases: detection and compensation phases. In the detection phase, we use the spatial position characteristic and histogram of backlight image to obtain two image indices, which can determine the backlight degree of an image. Fuzzy logic is then used to integrate these two indices into a final backlight index determining the final backlight degree of an image precisely. Second, in the compensation phase, to solve the over-saturation problem that exists usually in conventional image compensation methods, we propose the adaptive compensation-curve scheme to compensate and enhance the brightness of backlight images. The luminance of a backlight image is adjusted according to the compensation curve, which is adapted dynamically according to the backlight degree indicated by the backlight index estimated in the detection phase. The performance of the proposed technique is tested on 100 backlight images covering various kinds of backlight conditions and degrees. The experimental and comparison results clearly show the superiority of the proposed technique.