Validation of railway vehicle dynamic models in training simulators

Training simulators play an important role for sustaining safety, efficiency and cost effective railway transportation. Dynamic modelling of train systems is one of the main modules of training simulators. Validation of the dynamic models with collected real data ensures the fidelity of the simulator utilising the respective models. In this study, a validation process (Dynamic Modelling Validation Process (DyMVaP)) which is developed to support the validation of railway dynamic models is introduced. However, the proposed process can also be used in validating other dynamic models as well. The developed process is based on five steps including the preparation of validation scenarios, sensor deployment, real data collection, data preparation, and comparison of simulated and measured data. Note that the proposed DyMVaP was used for the validation of a full-mission training simulator so called TRENSIM, which was developed for Turkish State Railways. During the study it is realised that the current speed, travelled distance, acceleration (in x, y, z directions), rotation angles (around x, y, z axes), air pressure, in-train pressure/tension forces, traction motor currents, catenary voltage, positions of controllers must be collected synchronously by using proper sensors in order to ensure simulation validation. The required data was collected from locomotive body, bogies, wheel sets and connection of railway cars. The data (～200?GB) collected from the field by applying 27 different scenarios and transformed into appropriate data for utilising the generated dynamic models within the simulator. The measured and simulated data were also compared visually using graphical representation of the parameters as well as performing computations regarding the magnitude, phase and comprehensive error factors.     

Experimental and 3D,embedded modeling for diesel engine SCR deposit

Nowadays, the selective catalytic reduction (SCR) is a promising solution to fulfill stringent nitrogen oxide (NO_X) emission standards enforced by worldwide regulation bodies for lean burning engines. However, in the practical operation, urea deposits occur under unfavorable conditions, which bring about a failure of urea dosing strategy, affect the SCR system de-NOx performance and lowering the fuel economy by increasing the engine back pressure. This paper will present 3D deposit model, which can be used to predict the deposit position. Furthermore, a model-based controls strategy and calibration are designed. The comparison test results of both engine emission tests and vehicle field tests shows there is significant deposits improvement with the embedded model.     

Emission-robust operation of diesel HEV considering transient emissions

In this paper, we consider a method to create an engine emission simulation model for cycle and customer driving of a vehicle. The emission model results from an empiric approach, also taking into account the effects of engine dynamics on emissions. We analysed transient engine emissions in driving cycles and during representative customer driving profiles and created emission meta models. The analysis showed a significantly higher correlation in emissions when simulating realistic customer driving profiles using the created verified meta models (< 1 % model error) compared to static approaches, which are commonly used for vehicle simulation. Therefore, a transient modelling approach is conducted, which shows a great increase in accuracy in customer driving operation.     

Experimental investigations on continuous regenerative anti-lock braking system of full electric vehicle

Functions of anti-lock braking for full electric vehicles (EV) with individually controlled wheel drive can be realized through conventional brake system actuating friction brakes and regenerative brake system actuating electric motors. To analyze advantages and limitations of both variants of anti-lock braking systems (ABS), the presented study introduces results of experimental investigations obtained from proving ground tests of all-wheel drive EV. The brake performance is assessed for three different configurations: hydraulic ABS; regenerative ABS only on the front axle; blended hydraulic and regenerative ABS on the front axle and hydraulic ABS on the rear axle. The hydraulic ABS is based on a rule-based controller, and the continuous regenerative ABS uses the gain-scheduled proportional-integral direct slip control with feedforward and feedback control parts. The results of tests on low-friction road surface demonstrated that all the ABS configurations guarantee considerable reduction of the brake distance compared to the vehicle without ABS. In addition, braking manoeuvres with the regenerative ABS are characterized by accurate tracking of the reference wheel slip that results in less oscillatory time profile of the vehicle deceleration and, as consequence, in better driving comfort. The results of the presented experimental investigations can be used in the process of selection of ABS architecture for upcoming generations of full electric vehicles with individual wheel drive.     

Finite element damage analysis of an underwater glider–ship collision

Underwater gliders, which are profiling autonomous underwater vehicles designed to make oceanographic measurements, are increasingly used in the coastal ocean. As they regularly surface for data transmission, gliders increasingly pose a risk for fast ships. In order to estimate the extent of damage due to collision, 3D finite element simulations of collisions between a glider and a high-speed craft with a glass-fiber reinforced plastic hull are performed. Different collision scenarios such as impact locations, angles of attack and speeds are examined. The results are compared to an analytical solution based on simplifying assumptions. Although both methods reveal consistent results, it is shown that finite element simulations are required to account for the 3D shape of the ship. The results indicate that at ship velocities exceeding 7.5 m/s (14.6 kt) the glider penetrates the ship’s hull causing severe damage to its structure.     

特殊分段的精度控制方法探讨

在明确了分段精度控制意义及概念的前提下,对分段精度控制计划和精度控制管理过程作了详细分析,并制定相应的控制方法。首先针对舵臂分段,根据其尾部曲率较大以及不规则性,依据挂舵垂直性控制其精度;然后针对尾轴分段,根据同心度和尾轴管的定位控制该分段的精度;再针对主基座分段,主要根据基座面板水平度来控制该分段的精度;最后总结出典型分段精度控制方法。     

Path Planning of Planar Kinked Line Seam by Visual Servoing for Robotic Welding

Welding path planning can substitute for the manual teaching process of the robot and can promote the autonomous level of the robotic welding. A path planning method by visual servoing was presented, in which the optimal angle of charge-coupled device (CCD) camera was also planned. Aiming at planning two forms of kinked line seams, obtuse angle seam and right angle seam, a practicable solution was put forward. In this solution, the intersection of two adjacent straight segments is detected in each local seam image, and if intersection is found, theseam errors are calculated using the next straight segment. The experimental results show that kinked line seam can be well planned using this solution.     

一种自动提取车型图像边缘阈值算法的仿真研究

提出了一种利用改进的遗传算法自动选取车型图像边缘提取阈值的方法,使车型图像边缘能被完整地提取出来;从而达到识别汽车车型的目的。仿真结果表明:该算法节省了阈值的选取时间,增强了抗噪声性能,提高了车型识别率。     

Optimization of isolation structure under wind load excitation and experimental study of the wind resistant bearing

The method of collaborative work between steel plate anti-wind bearing (AWB) and rubber isolation bearing is proposed to study the vibration reduction effect of isolation structure under stronger wind load, and the function mechanism is explained. Based on a practical project, three kinds of schemes with different isolation layers are put forward, the finite element software ETABS is used for time history analysis, and comparison is made on the seismic response of different isolated structure and aseismic structure. Comparison result shows that the isolation layer with rubber bearing and AWB can work reasonably, but further optimization on the designed parameters is needed. Moreover, the design value of horizontal bearing capacity of lead rubber bearing (LRB) is appropriate to be close to the seismic isolation layer under wind load excitation. Finally, numerical simulation and comparative analysis of shear test of the AWB are conducted. With a very small yield displacement and yield strength over 80% of the set of horizontal bearing capacity, the AWB is validated to satisfy the working conditions which provide the horizontal bearing capacity under normal operating conditions and designed earthquake. The AWB yields and malfunctions, when the maximum displacement is less than the displacement of the isolation layer.     

Luminol-potassium permanganate chemiluminescence system for the determination of three anthracycline antibiotics

Objective To establish a flow-injection chemiluminescence method for the determination of doxorubicin, epirubicin and mitoxantrone and study its reaction mechanism. Methods In alkaline medium, chemiluminescence of luminol-potassium permanganate system could be inhibited obviously by anthracycline antibiotics. Combined with flow-injection technique, a new chemiluminescence method for determining the anthracycline antibiotics was set up. The chemiluminescence mechanism of the luminol-potassium permanganate system was also discussed. Results Under optimal conditions, the good linear ranges of doxorubicin, epirubicin and mitoxantrone were 5.0×10-9-1.0×10-6g/mL, 1.0×10-9-1.0×10-5g/mL and 3×10-9-1.0×10-6g/mL, respectively. The detection limits of doxorubicin, epirubicin and mitoxantrone were 3.0×10-9g/mL, 5.0×10-8g/mL and 2.0×10-9g/mL, respectively. During eleven repeated inter-day and intra-day precision tests of 1.0×10-6g/mL samples, the relative standard deviations corresponded to reference values of 3.0%, 2.8% and 2.1%. Conclusion The developed method is sensitive, accurate, rapid and of low cost. It can be applied to determine doxorubicin hydrochloride, epirubicin hydrochloride and mitoxantrone hydrochloride in injection preparations.