Hardware-software System for Exploring the Possibility of Application of CCD Image Sensors as Part of Gated-Viewing Systems

This paper presents the results of the development and testing of a system for studying the operating modes of CCD sensors. The purpose of the study is to verify the performance of these sensors as part of a gated-viewing system without using an image intensifier or another external fast shutter. The system can be used to control a commercial CCD sensor in an undocumented way using signals of arbitrary shape, synchronize its operation with a laser emitter, receive and digitally process an image, and transfer it to external devices. Experiments with various CCD sensors have shown that a gated-viewing surveillance system can be developed based on an interline transfer CCD sensor without an image intensifier and can be used in applications.     

Fretting at high temperatures

The fretting damage to an austenitic stainless steel, type 321, in CO₂ is much reduced at temperatures above 400°C by the formation of a glaze type oxide. Increasing the normal pressure from 2 to 6.9 MN m⁻² at 650°C greatly increased the extent and quality of the glaze. The nickel-based alloy, Inconel 718, developed glaze oxide when fretted at 540°C in air, as indicated by a low coefficient of friction and wear rate. At 280°C, the glaze was only found at greater amplitudes of slip. Although the titanium alloy Ti-6Al-4V in air at 200 to 400°C developed a surface oxide which had some of the superficial features of a glaze, it nevertheless did not reduce the coefficient of friction to values characteristic of glaze. The common feature of high-temperature alloys which develop protective glaze oxides is that they are capable under conditions of sliding and fretting of forming a spinel type oxide which, however, must be adequately supported by a creep-resistant substrate at the operating temperature     

Simulation of the continuous casting process by a mathematical model

A computational three-dimensional (3D) heat transfer model has been developed and applied to calculate the temperature distribution and solid shell thickness profile of a continous cast slab in a steel plant. This developed model includes non-linear material properties of specific heat and thermal conductivity as well as phase changes during solidification. A general thermo-fluidmechanics computer program, PHOENICS, was employed to numerically solve the heat transfer equation with the associated source terms. The thermal profile and solid shell thickness calculated by mathematical model agree with those predicted by an industrial model and experimental measurements. The model could also be used to predict the optimum process parameters on casting speed, heat removal rates and associated water flow rates and roll force. These parameters could be monitored by suitable sensors and controlled through a feed back system that interfaced with the mathematical model and the sensors.     

Quantitative analysis of a two-dimensional ice accretion on airfoils

This paper presents the development of a code that can determine the shape of accreted ice on a 2D airfoil, verification of the code via quantitative parameters, and the variation in ice accretion according to ambient conditions. First, the 2D panel method is used as the aerodynamic solver, and Messinger’s model is used as the thermodynamic model. Second, the code is quantitatively verified through comparison with existing ice accretion analysis codes under rime, mixture, and glaze ice conditions. The parameters for comparison are the cross-sectional area of the ice, maximum ice thickness, ice heading, and distribution of the ice thickness measured on the airfoil surface. The verification shows that the developed code yields results of similar accuracy to existing analysis codes. Finally, ice shapes, depending on variations in the ambient conditions, are determined and investigated based on these parameters for comparison. The selected ambient condition parameters are freestream velocity, LWC, and temperature. The investigation is carried out for rime and glaze conditions. Increasing the freestream velocity produces an ice horn that increases the area over which the ice encounters liquid water in the air. The ambient temperature is the factor that alters ice accretion behavior; increasing the ambient temperature turns rime ice into glaze ice. Ice accretion area is increased at higher LWC. The LWC and the ice cross-sectional area show a linear relationship.     

Design and development of a CCD based optical tomography measuring system for particle sizing identification

This research investigates the use of charge coupled device (abbreviated as CCD) linear image sensors in an optical tomographic instrumentation system used for sizing particles. Four CCD linear image sensors are configured around an octagonal shaped flow pipe for a four projections system. The measurement system is explained and uses four CCD linear image sensors consisting of 2048 pixels with a pixel size of 14 μm by 14 μm. Hence, a high-resolution system is produced. The designed instrumentation system is calibrated using known test pieces. Spherical shaped and irregular shaped particles are tested on the designed system to complete analysis of the overall performance of the system.     

基于PSoC的智能吸尘机器人控制系统的设计

主要研究了基于PSoC片上系统的智能吸尘机器人控制系统的设计，详细论述了控制系统的组成，推导了机器人的运动控制方程，设计了传感器检测电路。该控制系统灵活运用PSoC片上系统内部集成的PWM模块、计数模块和定时模块等来完成机器人的运动控制，通过运用红外传感电路和机械结构相结合的方法来检测外部环境信息。     

Integrated motion measurement illustrated by a cantilever beam

The combination of inertial sensors and satellite navigation receivers like those of GPS (Global Positioning System) represents a very typical integrated navigation system. Integrated navigation is the most common example of integrated motion measurement determining the translational and angular position, velocity, and acceleration of a vehicle. Traditionally, this object is assumed to be a rigid body and the signals of its closely spaced sensors are referenced to a single point of the structure. During periods of low vehicle dynamics such common navigation systems typically show stability problems due to a loss of observability of some of the motion variables.The range of applications for integrated navigation systems can be expanded due to the continuously increasing performance of data processing and cheap sensors. Further, it can be shown that the stability of such a navigation system (i. e. of the motion observer employed for the system, typically a Kalman filter) can be sustained by distributing appropriately additional sensors over the vehicle structures at distinct locations. This comprises the compensation of drift effects of the system by adding sensors that are drift-free and the guarantee of the observability of all estimated motion components. Large structures like airplanes, space stations, skyscrapers, and tower cranes with distributed sensors, however, have to take the flexibility of the structure into account. This includes an appropriate kinematical model of the structure. In this case, the theory of integrated systems has to be expanded to flexible structures. On the other hand, the additional system information obtained can be used not only for vehicle guidance but also for structural control.Within this work individual kinematical models especially of a cantilever beam, idealizing e.g. the wing of an airplane, are developed and investigated with regard to the observability of the motion variables to guarantee a stable integrated system behaviour. Finally, the application and verification of integrated measurement systems for flexible structures is shown by experiments.     

Performance evaluation of a cheap,open source,digital environmental monitor based on the Raspberry Pi

We report on the design, construction and evaluation of a low-cost digital environmental monitoring system based on a popular micro-computer board and mass market digital sensors. The system is based around the use of open source software and readily available digital sensors, providing key parameters required for environmentally-controlled calibration laboratories: air temperature, pressure and humidity. Each system logs data at set intervals with front-panel display, web page graphical display and email alerting when exceeding set tolerances. The sensors have been calibrated at the National Physical Laboratory using standards traceable to the SI. Long term stability of the system is estimated and in addition to monitoring of laboratory environments for regulatory purposes, the systems can also be used to provide on-demand values for local refractive index with an expanded (k = 2) uncertainty of 1.1 × 10⁻⁷ as required for many optical-based measuring systems.     

Development of coatings based on Fe-Cr-Ni-Al for resisting fretting wear in the temperature range 20–700 °C

Previous work by the present workers has indicated that sprayed molybdenum coatings on steel were beneficial in resisting fretting wear in the temperature range 20–300 °C. Beyond this temperature range the oxidation rate of molybdenum increased rapidly and limited its use. Such coatings were mixtures of metal and oxide and provided an elevated temperature “glaze” which appeared to lubricate the surface and to reduce significantly the level of fretting damage. In developing a coating for use over a wider temperature range, mixtures of elements were selected which would provide the possibility of surface glaze formation.Mixtures of Fe-Cr and Ni-Al alloys were arc sprayed onto a low alloy steel and tested under conditions of fretting at 20, 475 and 700 °C. Coatings containing iron and chromium developed a glaze oxide at 475 and 700 °C with resultant low wear. The nickel-based coating did not develop the glaze oxide at 475 °C but did so at 700 °C.     

Algorithm for calculating the eutectic point with active devices for detecting the formation of ice

Glaze sensors are intended for diagnosing the state of the surfaces of roads and runways of airports and allow determination of the freezing temperature and the concentration of aqueous solutions in the form of film precipitations deposited on the sensor surface. When antifreeze reagents fall on the snow or ice surface, their particles dissolve with the formation of a brine of varying concentration, which has a freezing temperature below that of water. In this case, a glaze sensor solves a double problem-to forecast the freezing temperature of a mixture and register the pavement pickling. The presented algorithm for calculating the eutectic point and concentration of salts allows evaluation of the above pavement characteristics from the sensor readings. Original Russian Text ? K.F. Ivanova, 2009, published in Pribory i Tekhnika Eksperimenta, 2009, No. 3, pp. 123–128.     

The application of force-sensing resistor sensors for measuring forces developed by the human hand

Most attempts to measure forces developed by the human hand have been implemented by placing force sensors on the object of interaction. Other researchers have placed sensors just on the subject's fingertips. In this paper, a system is described that measures forces over the entire hand using thin-film sensors and associated electronics. This system was developed by the authors and is able to obtain force readings from up to 60 thin-film sensors at rates of up to 400 samples/s per sensor. The sensors can be placed anywhere on the palm and/or fingers of the hand. The sensor readings, together with a video stream containing information about hand posture, are logged into a portable computer using a multiplexer, analogue-to-digital converter and software developed for the purpose. The system has been successfully used to measure forces involved in a range of everyday tasks such as driving a vehicle, lifting saucepans and hitting a golf ball. In the latter case, results are compared with those from an instrumented golf club. Future applications include the assessment of hand strength following disease, trauma or surgery, and to enable quantitative ergonomic investigations.     

The optimal design of a measurement system to measure the geometric errors of linear axes

In this paper, a measurement system consisting of an L-type reference mirror and five capacitive sensors is analyzed and optimized to measure the geometric errors of linear axes more accurately. The positions of the reference coordinate system and capacitive sensors are optimized to minimize the standard uncertainty of estimated geometric errors, which is due to the standard uncertainty of the component—the L-type reference mirror and the capacitive sensors. Primarily, the flatness of the L-type reference mirror and the linearity of the capacitive sensors cause the component uncertainties. The capacitive sensors fixed on the linear axis are moved, and the L-type reference mirror is fixed on the base of the machine tool to eliminate Abbe's error, which is proportional to the command position of a linear axis. Five geometric errors of a linear axis are measured with a single setup and single measurement, simply. Finally, the optimized measurement system is applied to measure the geometric errors of linear axes X and Y of a three-axis machine tool. And the standard uncertainties of the measured geometric errors are calculated based on the specifications of the L-type reference mirror and the capacitive sensors.     

一种新型智能清洁机器人测控系统的设计

介绍一种新型智能清洁机器人测控系统的设计与实现,采用8位单片机SST89E554RC作为控制器,移动轮采用2路直流电机独立驱动,由超声波传感器、红外反射式传感器、接触传感器及相关外围电路构成多传感器障碍物检测系统.     

Quiet zone tuning in a non-ideal sound field

Most active noise control (ANC) systems are designed and analyzed in ideal sound fields, where ANC performances are predictable with acceptable accuracies. In many ANC applications sound fields are non-ideal with significant differences between real ANC performances and theoretical predictions. If one uses an ideal model to optimize locations of actuators or error sensors for an ANC system in a non-ideal sound field, the actual quiet zone is inevitably different from its theoretical prediction. It is desired that users of ANC systems can tune quiet zones by adjusting ANC configurations, such as locations of secondary sources or error sensors. Model-independent ANC (MIANC) systems are preferred for this purpose. In this study, a model-independent ANC system is improved, implemented and applied to create a quiet zone in a non-ideal sound field. Users of the system can adjust locations of actuators or error sensors to tradeoff between sizes of quiet zones and levels of noise attenuations. Experimental results are presented to demonstrate observations and effects of quiet zone tuning using the improved ANC system.     

结晶釉的研究进展

简述了结晶釉在国内外的发展状况,着重介绍了硅锌矿结晶釉。特别介绍了一些硅锌矿结晶釉的氧化物添加剂及其对硅锌矿结晶釉影响机理的研究,并用几张结晶釉的偏光显微照片展示了硅锌矿结晶釉在显微分析方面的研究进展。     

Development and application of a system for evaluating the feed-drive errors on computer numerically controlled machine tools

This paper describes the development and application of a system for assessing the contouring characteristics of feed drives on computer numerically controlled (CNC) machine tools. The hardware comprises two linear digital displacement sensors mounted orthogonally on the work table of a CNC machine tool and operating against a precision cube, located in the spindle. Simultaneous movements of two machine axes are measured by the sensors, in conjunction with a microcomputer. Therefore, this system is capable of detecting the difference between a programmed and actual path. By using both circular and square corner programmed test paths, the system can evaluate servo-induced errors in machine tools. Application of the system to the X- and Y-axes of a machining center is undertaken, and results are shown for a range of contouring frequencies and gain settings of the axes. Comparative tests are also undertaken using a conventional double ball link bar, which is shown to be an inferior technique for characterizing the servoerrors.     

Model-based techniques for the testing and diagnosis of micro-manufacturing devices and machines

One of the main difficulties in developing a testing-and-diagnosis system for micro-manufacturing devices and machines is that the measurement process can require a high number of sensors, and is often too complex, in order to avoid external disturbances under normal working conditions, and the sensors are also not easy to allocate due to the minimal space available. At the present time, modern techniques of control-system engineering can be applied to propose a model-based testing and diagnosis methodology that reduces the number of the required sensors, due to a priori knowledge of the system expressed in terms of mathematical relationships between the physical variables. The Mechatronic Variable Estimation Library was created as a tool to estimate the value of “unknown” variables and parameters of the micro-device or machine using only a few sensors, reducing in this way the cost of the testing system and making the product of interest for industrial applications.     

On the vibro-acoustical operational modal analysis of a helicopter cabin

This paper aims to present a modal decomposition formulation for a vibro-acoustical operational modal analysis (OMA). In literature many works can be found on this topic, but until now no attention has been focused on the analytical form of the cross-power spectra (CPs) between the system outputs when a fluid–structure coupling is present. In this work it is shown that the CPs modal decomposition depends on the choice of the references, i.e. acoustical or structural. At first it is theoretically pointed out that the CP formulation for the acoustical and structural case is formally identical if appropriately pre-processed. Then, this theoretical result is verified through the results of an extensive experimental testing on the helicopter EUROCOPTER EC-135. The CPs between the structural output velocities and the acoustical response of the microphone inside the helicopter cabin are considered as inputs of an OMA. In order to verify the effectiveness of the modal model so obtained a classical modal analysis is also performed. The acoustical reference choice reveals to be suitable for a vibro-acoustical OMA. It is highlighted, indeed, that the acoustical pressure measurement inside the enclosure can be used as reference instead of the commonly used structural sensors, both from the theoretical and practical point of view. This is useful for high scale structures where the structural responses are usually measured by means of moving sensor arrays and additional fixed reference sensors should be positioned on the surface.     

Investigation into the wear behaviour of Stellite 6 during rotation as an unlubricated bearing at 600 °C

The wear behaviour of Stellite 6 was studied during rotational sliding in a bespoke bearing rig at 600 °C for times between 2 min and 12 h. Six stages of wear were identified: (i) formation of a mixed oxide ‘glaze’, (ii) cobalt and chromium elemental diffusion to the ‘glaze’ surface forming chromium- and cobalt-dominated oxide layers, (iii) oxygen diffusion into the ‘glaze’ leading to a chromium-dominated oxide layer at the ‘glaze’/substrate interface, (iv) spallation of the ‘glaze’ through chemical failure, (v) re-formation of the ‘glaze’ and (vi) elemental diffusion within the ‘glaze’, again resulting in discrete oxide layer formation.