No abstract

No abstract

In the present context of the global economic crisis and environmental emergency, transport science is asked to find innovative solutions to turn traditional vehicles into fuel-saving and eco-friendly devices. In the last few years, hybrid vehicles have been shown to have potential benefits in this sense. In this paper, the fuel economy of series hybrid-electric and hybrid-mechanical buses is simulated in two real driving situations: cold and hot weather driving in the city of Taranto, in Southern Italy. The numerical analysis is carried out by an inverse dynamic approach, where the bus speed is given as a velocity pattern measured in the field tests performed on one of the city bus routes. The city of Taranto drive schedule is simulated in a typical tempered climate condition and with a hot temperature, when the air conditioning system must be switched on for passenger comfort. The fuel consumptions of hybrid-electric and hybrid-mechanical buses are compared to each other and with a traditional bus powered by a diesel engine. It is shown that the series hybrid-electric vehicle outperforms both the traditional and the mechanical hybrid vehicles in the cold weather driving simulation, reducing the fuel consumption by about 35% with respect to the traditional diesel bus. However, it is also shown that the performance of the hybrid-electric bus gets dramatically worse when the air-cooling system is continuously turned on. In this situation, the fuel consumption of the three different technologies for city buses under investigation is comparable.

A position-controlled pneumatic actuator using pulsewidth modulation (PWM) valve pulsing algorithms is described. The system consists of a standard doubleacting cylinder controlled with two three-way solenoid valves through a 12-bit A/D PC board. The mechatronic system has the advantage of using o d o f f solenoid valves in piace of more expensive servo valves and it may be applied to a variety of practical positioning applications. A proportional integrative (PI) controller with position feedforward is successfully implemented. Several experimental tests are carried out to evaluate the robustness of the control system and the performances of a novel pulse-width modulation algorithm implemented. The actuator's overall performance is comparable to that achieved by other researchers using servo valves.

No abstract

In the last few years, various control systems have been investigated in the automotive field with the aim of increasing the level of safety and stability, avoid roll-over, and customise handling characteristics. One critical issue connected with their integration is the lack of state and parameter information.As an example, vehicle handling depends to a large extent on tyre inflation pressure. When inflation pressure drops, handling and comfort performance generally deteriorate. In addition, it results in an increase in fuel consumption and in a decrease in lifetime. Therefore, it is important to keep tyres within the normal inflation pressure range. This paper introduces a model-based approach to estimate online tyre inflation pressure. First, basic vertical dynamic modelling of the vehicle is discussed. Then, a parameter estimation framework for dynamic analysis is presented. Several important vehicle parameters including tyre inflation pressure can be estimated using the estimated states. This method aims to work during normal driving using information from standard sensors only. On the one hand, the driver is informed about the inflation pressure and he is warned for sudden changes. On the other hand, accurate estimation of the vehicle states is available as possible input to onboard control systems.

Ground autonomous mobile robots have important applications, such as reconnaissance, patrol, planetary exploration, and military applications. In order to accomplish tasks on rough terrain, control and planning methods must consider the physical characteristics of the vehicle and of its environment. Failure to understand these characteristics could lead to vehicle endangement and consequent mission failure. This paper describes recent and current work at the Politecnico of Bari in collaboration with the University of Lecce in the area of deformable terrain mobility and sensing. A cylindrical mobile robot is presented and its rolling motion on terrain is studied from a theoretical and experimental prospect. A comprehensive model is developed taking into account the interaction of the vehicle with the terrain and the related dynamic ill effects, such as rolling resistance and slip, and it is experimentally validated. An unconventional application of the vehicle serving as a tactile sensor is discussed and experimental results are presented showing the effectiveness of the cylindrical mobile robot in estimating the properties of homogeneous, deformable terrain, which in turn can be used to assess the vehicle traversability.

No abstract