也谈“辅车相依”

本文在前人研究的基础上 ,从训诂学和文学语言等方面 ,试图对“辅车相依”一语中的“辅”、“车”做出更加合乎原文和逻辑的解释 ,认为“辅”、“车”的意义都应同车有关。

Optimal path finding algorithms based on SLSD road network model

A solution to compute the optimal path based on a single-line-single-directional（SLSD）road network model is proposed.Unlike the traditional road network model,in the SLSD conceptual model,being single-directional and single-line style,a road is no longer a linkage of road nodes but abstracted as a network node.Similarly,a road node is abstracted as the linkage of two ordered single-directional roads.This model can describe turn restrictions,circular roads,and other real scenarios usually described using a super-graph.Then a computing framework for optimal path finding（OPF）is presented.It is proved that classical Dijkstra and A algorithms can be directly used for OPF computing of any real-world road networks by transferring a super-graph to an SLSD network.Finally,using Singapore road network data,the proposed conceptual model and its corresponding optimal path finding algorithms are validated using a two-step optimal path finding algorithm with a pre-computing strategy based on the SLSD road network.

New Method to Restrain Pumping Voltage of Braking Procedure for Brushless DC Motor of Electric Armored Vehicle

In order to restrain the high pumping voltage of braking procedure which is harmful to the system of electric armored vehicle. Based on the analysis of pumping voltage of the braking procedure, the relation between pumping voltage and PWM ratio is derived and a new digital control method to restrain the pumping voltage by changing PWM ratio is put forward. Because the capacitance is decreased effectively, the volume of controller is reduced and the performance to price ratio is improved. The results of computer simulation and experiment proved that this method is feasible and valid.

Design and Development of the DTC Induction Motor Drive for Electric Vehicle

The design and development of the traction controller for electric vehicle is introduced, which is based on the induction motor. This drive is developed by using a digital signal processor at low cost and carried out with the module design concept of both software and hardware. Nevertheless, a scheme of the sensorless direct torque control is based on the developed hardware, of which the feasibility is tested by a trial program. Additionally, both the interface function of the drive hardware and the feasibility of its software are proved to be good by the trail programs. A test motor can run about 18?r/min by a variable frequency program with the space vector pulse width modulation technology, of which the torque is visible pulsatile. In this presentation, based on the theoretical approach, the sensorless torque control is to be studied and applied to electric vehicles, of which the quick, smooth and stable torque response is emphasized because it quite benefits improving the drive performance of electric vehicles.

Three-dimensional visualization interactive system for digital twin workshop

To improve the human-physical-virtual coordination and integration of the digital twin workshop,3D visual monitoring and human-computer interaction of the digital twin workshop was studied.First,a novel 6D model of the 3D visualization interactive system for digital twin workshops is proposed.As the traditional 5D digital twin model ignores the importance of human-computer interaction,a new dimension of the user terminal was added.A hierarchical real-time data-driven mapping model for the workshop production process is then proposed.Moreover,a real-time data acquisition method for the industrial Internet of things is proposed based on OPC UA(object linking and embedding for process control unified architecture).Based on the 6D model of the system,the process of creating a 3D visualization virtual environment based on virtual reality is introduced,in addition to a data-driven process based on the data management cloud platform.Finally,the 6D model of the system was confirmed using the blade rotor test workshop as the object,and a 3D visualization interactive system is developed.The results show that the system is more transparent,real-time,data-driven and more efficient,as well as promotes the coordination and integration of human-physical-virtual,which has practical significance for developing digital twin workshops.

Applied research on reliable increase measures of CNC lathes

According to the reliable data of sixteen CNC lathes, each reliable index of the serial CNC lathes is evaluated before tackling and after tackling. According to the failure analysis, reliable improvement measures of the serial CNC lathes are put forward.

Stability influence factors analysis and construction of a deep beam anchorage structure in roadway roof

Deep beam anchorage structures based on spatial distribution analysis of the cable prestressed field have been proposed for roadway roof support, Stability and other factors that influence deep beam structures are studied in this paper using mechanical calculations, numerical analysis and field measurements, A mechanical model of deep beam structure subjected to multiple loading is established, including analysis of roof support in the return airway of S1203 working face in the Yuwu coal mine, China, The expression of maximum shear stress in the deep beam structure is deduced according to the stress superposition criterion, It is found that the primary factors affecting deep beam structure stability are deep beam thickness, cable pre-tension and cable spacing, The variation of maximum shear stress distribution and prestressed field diffusion effects according to various factors are analyzed using Matlah and FLAC3DTM software, and practical support parameters of the S1203 return airway roof are determined, According to the observations of rock pressure, there is no evidence of roof separation, and the maximum values of roof subsidence and convergence of wall rock are 72 and 48 mm, respectively, The results show that the proposed roof support design with a deep beam structure is feasible and achieves effective control of the roadway roof,

Research on coal roadway truss and numerical simulation of bolting support effect

According to the research results in world, the paper comprehensively analyzed and gave a demonstration of mechanism of single-truss and its stressing advantage. Comparison and analysis effect were given to single-truss and bolting supporting. By the way of element simulation. The paper shows that single truss supporting have better effect to bolting supporting to improving the stress condition of surrounding rocks, controlling the surrounding rocks plastic failure development zone and deformation effect of surrounding rocks, which provided the elementary theory basis to the research, experiment and expanding the single-truss bolting technology in colliery.

Modeling the special intersections for enhanced digital map

A new lane-level road modeling method based on cardinal spline is proposed for the special intersections which are covered by vegetation or artificial landscape in their central regions.First,cardinal spline curves are used to fit the virtual lanes inside special intersections,and an initial road model is established using a series of control points and tension parameters.Then,the progressive optimization algorithm is proposed to determine the final road model based on the initial model.The algorithm determines reasonable control points and optimal tension parameters according to the degree of road curvature changes,so as to achieve a balance between the efficiency and reliability of the road model.Finally,the proposed intersection model is verified and evaluated through experiments.The results show that this method can effectively describe the lane-level topological relationship and geometric details of this kind of special intersection where the central area is covered by vegetation or artificial landscape,and can achieve a good balance between the efficiency and reliability of the road model.

Digitalization of mine operations:Scenarios to benefit in real-time truck dispatching

One of the key factors in a profitable open-pit mine is the efficiency of the waste disposal system. Using GPS-technology, the truck-dispatching decisions can be made in real-time but the chosen strategy has a crucial role. Therefore, finding the optimal dispatching strategy for truck-shovel operations is extremely important. Dispatching strategies have been reported in the literature, but the comparison of these strategies is still missing. This paper illustrates the differences between the strategies by conducting a stochastic simulation study based on the data gathered from an actual mine. The findings underline the importance of the global vision in dispatching decisions.

Intelligent Vehicle Driving Controller Design and Implementation Evaluation

An intelligent vehicle control system is designed and embedded in a Digital Signal Processing （DSP） platform （eZdspTM F2812）. A golf cart is used as an installation platform for the overall system, including steering wheel Alternating Current （AC） serve motor, brake actuator, throttle driving circuit and sensors. Digital image processing technology is also used to enable the autonomous driving system to achieve multi-mode lane-keeping, lane-change and obstacle-avoidance. The overall system is tested and evaluated on a university campus.

Delay Analysis and Formulation Inference of Signalized Intersection for Traffic Congestion Conditions

Vehicle delay is an important measure to evaluate the signal timings of signalized intersections.When optimization the signal control parameters, delays of vehicles from all approach directions of an intersection should be considered. Based on the analysis of the vehicle delay on an approach of intersection, directed against the typical condition of a congested intersection-over-saturated condition, the paper has analyzed and inferred the intersection delay dynamic formulation, and has established the relation between intersection delay,the signal timings, vehicle arrival rate and the queue lengths, and that provides useful information for understanding vehicle delay of signalized intersection and for establishing performance index function of signal timing optimization.

Human Factors in the Analysis of the ＂Tram-Car Drivers＂ at Intersections

The modem tramway has resurfaced as the cure to today＇s urban transport problems such as pollution, road congestion and uneven access to transit. However, trams at intersections often experience frequent and extended delays due to vehicles crossing the tram tracks. There is an increased potential for conflict between trams and vehicles at these locations and crashes are common. The question of the effects of human factors on trams crossroads safety has been little dealt with in literature. The general aim of this article is to further knowledge about the influence of tramway and surrounding environment on car＇s driver behavior at intersections. Understanding these influences, involve conducting a systematic review of the cognitive tasks related to driving and identifying the hazards that can arise at each task, and what factors can make these more or less likely to arise, considering the environmental design at intersections and behavioral factors. To achieve that, the HAZOP （Hazard and Operability Study） approach is conducted for this study. Concerning data collection, the methodology includes site visits to record user behavior and questionnaires to determine the opinion, concerns and knowledge of car drivers in interaction with the tram environment.

Cellular Automata Model for a Specific Traffic Regime and 1/f Noise

We examine the traffic lights regime to enable the fastest overall approach to a city for a specific case. The case involves a traffic light where one continues on the main road, into which additional cars are entering at the light. At this intersection an alternative route begins, which is longer but into which no additional cars are entering. To keep the total number of vehicles constant, we subtract on the main road far from the intersection, the same number of cars as were added at the intersection. In addition to checking different densities we check also the influence of changes in the number of cars which were added. We calculate the Fourier transform of the average on each traffic light cycles of the velocity on the main road and bypass. We obtained different results for different cases. All the cases can be written as 1/fa .

Influence of aerodynamic braking on the pressure wave of a crossing high-speed train

When aerodynamic braking works,the braking wings can change the flow field around the train,which may impact on the comfort and safety.Based on a sliding mesh,the pressure wave and flow field around high-speed trains with aerodynamic braking are analyzed.By comparing three typical intersection situations,the pressure wave of a high-speed train during braking (with or without aerodynamic braking) is studied.The analyses indicate that the pressure wave around the high-speed train body will change while using the aerodynamic braking,causing several pressure pulses on the surface of crossing high-speed trains.The distances between the pressure pulses are equal to the longitudinal distances of the brake wings,but the magnitudes of the fluctuations are less than those induced by the head of crossing trains.During the crossing,a train without aerodynamic braking will not impact the crossing train.

Unsteady simulation for a high-speed train entering a tunnel

In order to study the unsteady aerodynamics effects in railway tunnels,the 3D Reynolds average Navier-Stokes equations of a viscous compressible fluid are solved,and the two-equation k-ε model is used in the simulation of turbulence,while the dynamic grid technique is employed for moving bodies.We focus on obtaining the changing tendencies of the aerodynamic force of the train and the aerodynamic pressures on the tunnel wall and train surface,and discovering the relationship between the velocity of the train and the intensity of the micro pressure wave at the tunnel exit.It is shown that the amplitudes of the pressure changes in the tunnel and on the train surface are both approximately proportional to the square of the train speed,so are the microwave and the drag of the train.

A study on flow fields and performance of water wheel turbine using experimental and numerical analyses

In this paper, an analysis of the performance and flow fields of water wheel turbines for tidal energy extraction is carried out using experimental and numerical methods. The purpose of this work is to develop a water turbine suitable for sites, where fast and shallow surface flows are available, such as rivers or tidal currents. For both methods, the water wheel turbine is tested over a range of tip speed ratios with a differing number of rotor blades, ranging between three and twelve. The results indicate that the numerical simulation shows agreement with the experiment in most cases. Also, the water wheel turbine operates effectively at a range of small tip-speed ratios, where the highest turbine efficiency is produced. Under the same working conditions, the turbines using between six and nine blades generate a greater efficiency and cause lesser reverse flows than others when submerged in water. In contrast, the 3-bladed turbine is the least efficient design as it produces the lowest amount of energy and causes intense vibrations and noises. These noises are a result of a collision between the incoming flow of the channel and the wheel blades during the experimentation, especially at high load conditions. By adding more blades, the torque generated is improved considerably; however, the upstream and downstream depths of the turbine, in this case, are also elevated significantly.Furthermore, in the inlet region, the 3-bladed and 6-bladed turbines have a smaller shock loss and a lower resistance to the main flow from the inlet than the others. Meanwhile, it is found that the flow in the outlet region on the turbines with between nine and twelve blades is in the opposite direction to the wheel's rotation, significantly obstructing the main flow from the inlet.