Sensitivity of the Spool Rate on the Dynamic Response of the System

In rotodynamic systems, the rotor is spooled up from zero speed to its operating speed during the engine start. One of the considerations in design of rotating systems is the placement of rotor critical speed. It is vital to ensure that the rotor critical speeds are not close to the engine operating speed. However, it is not always possible to isolate all the frequencies above the operating speed. So, during the engine start to full speed, rotor system does travel through the mode. Therefore, to avoid a large system response, the rotor is spooled up quickly through the critical speed. In addition to the rotor critical speeds, the natural frequencies of the static structures may also get excited during the rotor spool up and spool down. The static structure response is one of the important considerations in designing a system for dynamic loading condition. It has been observed that the rotor spool rate affects the static structure response. This paper focuses on effect on system’s response under various spool rate. It has also been shown that the natural frequency of the system and damping in the system are two of the major factors towards sensitivity of system response with spool rate. Additionally, it has been observed that the presence of non-linearities shifts the peak response away from the natural frequency depending on the spool rate and spool direction.

An investigation of flux characteristic in direct torque control using sector rotation strategy

Stator flux fails to regulate at low operating speed condition is a common drawback for the conventional DTC. It is due to the inevitable of voltage drop across the stator resistance that interrupts the controlling of stator flux in DTC. Hence, a fixed sector rotation strategy is one of the solutions to rectify the raised issue. The strategy is based on the decreasing stator flux droop, which is an easy technique to change the sector of flux locus at a specific angle. However, this strategy only focuses at low operating speed. Thus, the stator flux droop effect at the various speed needs to be analysed. In this paper, an investigation is conducted by using simulation (MATLAB/Simulink) and experimental setup (dSPACE board) where a good agreement has been achieved between the predicted and measured results. The analysis taking into account between the conventional method (without strategy) and the proposed method (with strategy). In conclusion, the influence of stator flux droop is inversely proportional to the operating speed.

Operating Speed Prediction Models for Tangent Segments: A Brief Review

This paper provides a review of studies aimed at developing operating speed prediction models for road tangent sections. The review included many studies, conducted in different geographical areas of the world, in terms of road classification, types of vehicles, techniques and devices used in data collection, number of study sites, the principle adopted in extracting the free-flow speed, as well as the topography that the road path passes through and grads of the studied sections. Moreover, this review mentioned the analysis methods adopted in the modeling, and included the model formulas that the researchers have reached in their studies, as it showed all the geometric elements and traffic characteristics that appeared in the models as independent variables. The author has avoided critiquing or evaluating the methodologies of the reviewed research and accordingly this paper has been prepared for documentation only. The author aims primarily to save the effort and time of graduate students and researchers interested in modeling the operating speed on straight segments, as all data and information are arranged in tables and coordinated for this purpose. Doi: 10.28991/cej-2021-03091784 Full Text: PDF

Review and analysis of roadway crash prediction studies on urban roads under heterogeneous traffic conditions

In recent decades, pre-predicting the roadway accidents is essential for real time traffic incident management that effectively minimizes the environmental pollution, traffic congestion and secondary incidents. Currently, the traffic data are available in thousands of public and private datasets and also generates terabytes of data each year. Though, it is infeasible to manage the huge datasets by utilizing traditional software and hardware. It is therefore essential that an automated system to predict road accidents is developed. The present review paper investigates the researches done on road accident prediction, particularly for urban roads under heterogeneous traffic conditions. It also explores the problems faced in existing works by researchers. This review paper helps researchers achieve a better solution for the current problems faced by heterogeneous traffic conditions when it comes to urban road accident prediction. The findings demonstrate that the operating speed and the disparities between the speed restrictions and the operating speed are the key factors influencing the accident frequency rate.

Combining the Advantages of Different Processing Solutions Using a Novel Motion Processing Approach

In processing machines, technological tasks are implemented using suitable processing solutions. Those processing solutions can in turn have very different characteristics and specific advantages and disadvantages, e.g., concerning sensitivity to changing operating speed. In state-of-the-art processing machine controls, executing one single processing solution is supported. The execution of various processing solutions together and the combination of their advantages is currently not supported at all. In this article, a motion control approach is discussed that allows combining seemingly incompatible process solutions for a given technological task into a hybrid process solution, using the example of processing machines. The objective of this approach is to increase the achievable process window of the machine in terms of operating speed. It is shown that combining different process solutions can merge their advantages and compensate for their disadvantages. The article brings together the lessons learned from previous work in a new application to exploit advantages and compensate for disadvantages.

Automatic Data Processes

Well, the data process is created by the need to process the data more quickly and efficiently since the manual process that was carried out no longer met the expectations of people and companies, for this reason the data process arises automatic. In an automatic data process, the computer has different physical elements that allow it to carry out these same processes. That is, practically the speed of operation of the system is limited by human control. The entry by electromechanical type machines, as well as the exit, have a higher operating speed than the conventional one (until then this was achieved by tachy-typing). We can define data processing as the technique of converting data into information by any means, whether manual or automatic. Manual data processing is the technique of converting data into information using tools such as pencil, pens, typewriters, etc. The automatic data process within its objectives is the technique of converting data into information using appropriate methods, procedures and equipment for this purpose; such as interviews, surveys, computer. Automatic data processing came to renew the world, creating a special science for its study, such as computer science.