Direct yaw moment control and power consumption of in-wheel motor vehicle in steady-state turning

Driving force distribution control is one of the characteristic performance aspects of in-wheel motor vehicles and various methods have been developed to control direct yaw moment while turning. However, while these controls significantly enhance vehicle dynamic performance, the additional power required to control vehicle motion still remains to be clarified. This paper constructed new formulae of the mechanism by which direct yaw moment alters the cornering resistance and mechanical power of all wheels based on a simple bicycle model, including the electric loss of the motors and the inverters. These formulation results were validated by an actual test vehicle equipped with in-wheel motors in steady-state turning. The validated theory was also applied to a comparison of several different driving force distribution mechanisms from the standpoint of innate mechanical power.     

前处理废弃物零排放(3R化)技术

涂装前处理采用的是磷酸锌处理工艺,各工艺的排水和成膜时产生的磷化沉渣成为废弃物。介绍了从新开发的药剂着手减少沉渣和排水量的技术,以及将产生的排水污泥和沉渣作为原料再利用等前处理废弃物的3R化(Reduce、Recycle、Reuse)技术及其今后的课题。     

Parametric rolling prediction in irregular seas using combination of deterministic ship dynamics and probabilistic wave theory

In recent years there have been reports of serious accidents of parametric rolling for modern container ships and car carriers. For avoiding such accidents, a prediction method of parametric rolling in irregular seas is required. Since parametric rolling is practically non-ergodic, repetitions of numerical simulations or experiments could be not feasible to ascertain the behaviour. Therefore, in this paper, a method combining a stochastic approach with a deterministic approach in order to estimate the probabilistic index without such simple repetitions is developed. The ship's response in regular seas is estimated by solving an averaged system of the original 1-DoF roll model, and random waves necessary for occurrence of parametric rolling is achieved by using Longuet-Higgins’s or Kimura’s wave group theory. As a result, a fast and robust computation method of the probabilistic index is established. Finally, it is concluded that the proposed method is considered to be one of the useful tools for discussing the new IMO Intact Stability Code.     

Assessment of ship evacuations in response to pending tsunamis

Earthquakes occur due to friction between two geological plates. Historically, numerous earthquakes have occurred in the southern Sea of Japan. As of January 2008, the estimated probability of occurrence of the next Nankai or Tonankai earthquake within the next 30 years has been set at 50 or 60–70%, respectively. Should either of these earthquakes occur, a tsunami resulting in great horizontal movement and force could also result, setting numerous vessels adrift inside ports, causing destruction to port facilities, and endangering human life inside the vessels. Thus, appropriate countermeasures are required for ships because they may be forced to change locations unexpectedly. To minimize the probability of disaster should a tsunami forecast be issued, all vessels in Osaka Bay will need to evacuate immediately and proceed to safe anchorage areas before the tsunami arrives. However, the orderly evacuation of ships to safe anchorage areas would face difficulties due to traffic density within the Osaka Port area, and so appropriate improvements to ship traffic management are required. In this paper, several vessel-related issues, such as inter-ship distances, evacuation order procedures prior to the arrival of the first tsunami, and the first peak tsunami arrival time, are evaluated using general discrete event simulation.     

Development of ship sinking frequency model over Subsea Pipeline for Madura Strait using AIS data

It is important to study the risk posed by heavy shipping traffic to a subsea pipeline located near an industrial port area. In this context, it is essential to estimate the accident frequency in an attempt to eliminate subjectivity in the analysis process. This study proposes a model for estimating the ship sinking frequency over the subsea pipeline in the Madura Strait area. The Madura Strait is one of the busiest shipping lanes in Indonesia. Many ships pass through the fairway in the strait, and many industrial ports have been built in this area. The proposed model is developed based on Fujii’s Model, and it uses Automatic Identification System (AIS) data as a ship traffic survey. Ship sinking accidents are considered based on ship–ship collisions over the critical subsea pipeline area. The ship–ship collision locations around the subsea pipeline and the ship traffic distribution models are estimated using AIS data. The causation probability Pc is determined based on a synthetics approach using a Bayesian network modified from Det Norske Veritas’ and Hänninen’s models. The causation probability is estimated by considering factors such as human performance, weather, technical problems, and support. The proposed model is validated by comparing its result with actual accident records for the Madura Strait area. The ratio value of 0.33 is considered to be reasonably agreement (ratio value ≥0.2).     

Use of simulators in assessment,learning and teaching of mariners

High standard shipping is to a large extent dependent on the availability of high standard human resources both at sea and ashore. High standard human resources at sea require well-qualified mariners who are capable of navigating ships safely. Numerous maritime accidents and incidents have highlighted the crucial role that mariners have in avoiding casualties and maintaining clean oceans.     

Case study on health assessments related to a modal shift in transportation

Historically, the emphasis on environmental problems has been on visible pollution. However, as a result of the reduction in visible pollution in recent years, many people have become anxious about invisible dangers. The method for objectively evaluating these invisible dangers is risk assessment. Therefore, in the present study we propose and discuss a method for evaluating the influence of a modal shift in transportation on cancer risk using the technique of risk assessment. First, two representative transportation routes were selected for analysis. Subsequently, the level of airborne carcinogens from the exhaust of ships and trucks was determined. Next, the concentration of each carcinogen in locations across Japan was calculated. Finally, the number of people in Japan who will suffer from cancer related to these emissions was derived and the effects of the modal shift on health are discussed.     

A new weather-routing system that accounts for ship stability based on a real-coded genetic algorithm

The operation schedule of an oceangoing vessel can be influenced by wave or wind disturbances, and is therefore weather routed. The weather-routing problem is considered to be a multimodal function problem. Therefore, in the present research, the real-coded genetic algorithm technique (an evolutionary calculation technique) is applied to globally search for the optimum route. Additionally, to avoid maritime accidents due to parametric rolling, this route optimization method takes into account the risk of parametric rolling as one of its objective functions. Numerical verification is carried out for three kinds of objective functions with different weight ratios between fuel efficiency and ship safety in parametric rolling. As a result, it is numerically confirmed that the relation between economics and ship safety is a trade-off, and the safer route is not necessarily the most economical. Considering its robustness, the proposed method appears to be a powerful practical tool by choosing the most appropriate weights for economics and ship safety.