Real-Time Fuzzy Obstacle Avoidance Using Directional Visual Perception

This paper presents a novel vision-based obstacle avoidance approach for the Autonomous Mobile Robot (AMR) with a PanTilt-Zoom (PTZ) camera as its only sensing modality. The approach combines the morphological closing operation based on Sobel Edge Detection Operation and the (μ-kσ) thresholding technique to detect obstacles to soften the various lighting and ground floor effects. Both the morphology method and thresholding technique are computationaUy simple. The processing speed of the algorithm is fast enough to avoid some active obstacles. In addition, this approach takes into account the history obstacle effects on the current state. Fuzzy logic is used to control the behaviors of AMR as it navigates in the environment. All behaviors run concurrendy and generate motor response solely based on vision perception. A priority based on subsumption coordinator selects the most appropriate response to direct the AMR away from obstacles. Validation of the proposed approach is done on a Pioneer 1 mobile robot.     

俄罗斯铁路解决机车不足的问题

至2010年前俄罗斯将淘汰大部分旧机车,但据估计其货运量到2010年将增加26%,客运量增加6%～7%.为满足运输量增长的要求,俄罗斯铁路需要约6 800台电力机车和6 500台内燃机车.文章介绍了俄罗斯制定的机车战略决策.     

Modelling and Control of an Automated Vehicle

We present a vehicle model that includes the vehicle dynamics and a vehicle tire model. The model developed is then used for conducting steering analysis of an automated vehicle. We test the developed model on a step lane change maneuver and propose a model-reference based controller for remote control of a vehicle. Stability analysis of the closed-loop system using die Lyapunov approach is included.     

The social psychological consequence of a life at sea: A causal model

This paper explores the influence of this occupation on alienation and social integration of its members. Data were collected using a survey instrument from a sample of 293 seamen, both officers and crew. Factors determining variance in levels of alienation are examined using multiple regression technique. Results indicate that variance in several occupational features of life at sea affect the degree of alienation experienced by seamen, and a number of social characteristics were found to mitigate these influences. Supplementary qualitative data are also used.     

Investigation on evaluation of yaw stability for medium commercial vehicles

This paper proposes test scenarios for evaluation of yaw stability for medium commercial vehicles. Maneuvering, speed, longitudinal tire force, tire-road friction coefficient, road slope, and load condition are considerable factors that have effect on the medium commercial vehicle yaw stability. After conducting an analysis on these six factors, effective test scenarios were developed. A sine with dwell test is well known as a test scenario for evaluation of performance of electronic stability control (ESC) on passenger vehicles and heavy commercial vehicles. The SWD test was modified considering medium commercial vehicle dynamics, and the ramp steer maneuver with maximum acceleration test was proposed. Simulation validation has been conducted using field test data. From simulation study, it was shown that the ESC system for medium commercial vehicle is effectively evaluated by the proposed test scenarios.     

Engine clutch torque estimation for parallel-type hybrid electric vehicles

This paper mainly focuses on the accurate estimation of the torque transferred through the engine clutch installed between the engine and the drive motor in parallel-type hybrid electric vehicles. The estimation of the engine clutch torque primarily relies on the forward-direction observer which uses the nominal engine net torque information. To overcome the limitation of using the nominal engine torque information that it may not be accurate during the transient states or due to the influence of external disturbance such as the road condition and wind, the forward-direction observer is supplemented by the use of reverse-direction observer which uses the driveline model and wheel speed measurements. In addition, the drive motor torque information is used to calibrate the nominal engine torque during the idle charging state, so that the driveline characteristic unique to parallel-type hybrid electric vehicle can be utilized to increase the estimation accuracy. Finally, the estimation performance of the designed observer is tested via simulation and experiments based on a real vehicle.     

Subjective absolute discomfort threshold due to idle vibration in passenger vehicles according to sitting posture

Idle vibration, occurring when a vehicle comes to a stop while the engine is on, is known to be a main cause of discomfort for passengers, and the customer effect has been recently growing. The frequency of idle vibration is determined by the engine type. To lower the vibration, various technologies have been applied to optimize the engine mount and vehicle body structure. In addition to the technological developments, research on human response with a consideration of idle vibration is needed to effectively reduce the level of discomfort experienced by passengers. Seats aimed at enhancing static comfort influence the sitting posture of passengers; sitting posture is a factor affecting human body characteristics that response to idle vibration. This study examined the absolute discomfort threshold of idle vibration according to the sitting postures of 13 taxi drivers. The four sitting postures of subjects on a rigid-body seat without a backrest were variables in the determination of absolute discomfort threshold of idle vibration. The absolute discomfort threshold curves obtained in this experiment were less sensitive to frequency changes than the frequency weighting function of ISO 2631-1.     

Static Load Test of Low Vibration Track under Heavy Haul TrainEI北大核心

Research purposes: Low vibration track is a suitable track structure in the heavy haul railway long tunnel. Taking the low vibration track in the middle-south channel tunnel as the research object, through the full-scale model static load test, this paper studies the mechanical properties of a single bearing block under the vertical load at the end of the track bed slab (working condition 1), the horizontal and vertical load at the end of the track bed slab (working condition 2), the vertical load at the middle of the track bed slab (working condition 3) and track's crack development trend. Research conclusions:(1) Taking the static load of 30 t axle load train as a reference, the track slab and bearing block concrete of working condition 1 reach the axial tensile strength at 3.3 and 3.1 times static wheel load, the track slab and bearing block concrete of working condition 2 reach the axial tensile strength at 3.0 and 3.1 times static wheel load, the track slab and bearing block concrete of working condition 3 reach the axial tensile strength at 4.9 and 2.9 times static wheel load. (2) Track slab's crack of working condition 1 appears at the corner of the bearing block and the midline of the long side of the bearing block and extends to the short side of the track slab. The crack extension at the corner point is in the shape of "eight". There is no obvious crack of working condition 3 in the track slab. (3) The horizontal load of the train leads to the increase of the force of the concrete in the corner of the bearing block. (4)The research results have guiding significance for the design, construction and maintenance of low vibration track. © 2018, Editorial Department of Journal of Railway Engineering Society. All right reserved.     

High-Speed Rail Operations on an Existing Network: An Assessment Model for China

High-speed rail operations have the potential to reduce the long-term decline in rail passenger travel demand for the medium to long distance inter-urban markets. Such decline has been evident through most of the industrialized countries where air and road transport tend to be the dominant modes. In China, the operations of long distance high-speed rail on fully dedicated track is not very easy to implement, due to the high proportion of passengers who travel between high-speed and conventional railways. An alternative approach would be to allow for mixed operations with trains of various speeds on the same track. This article puts forward a simulation model designed to allow an evaluation of the most efficient distance for high-speed rail operations under mixed train speed scenarios. The model takes into account the main operating parameters such as passenger volumes, train speeds, capital and maintenance costs, train operating costs and energy consumption. The distance of high-speed train running on conventional rail that will yield the most economic benefit can be estimated using the model. The article includes the results of using the model for a specific example. It is concluded that large-scale high-speed trains have the potential to be successfully operated on conventional rail networks.