This paper describes an electric wheelchair using a fuel cell and its speed characteristics. The wheelchair system has a PEM fuel cell stack as a power supply, an EDLC bank as an energy buffer, and a newly designed four-quadrant DC chopper which drives two DC motors. Drive performance of the wheelchair and essential characteristics of the fuel cell are investigated by experimental results. Consequently, it is shown that the wheelchair satisfies basic driving operations, and also the PEM fuel cell has sufficient capability for the wheelchair system. Therefore, the ideas and technologies which are applied to the system will be able to contribute to future electric vehicles and transportation.
Throttle holes area of telescopic shock absorber for electric vehicles influence the ride comfort, driving harshness and the other parameters design. For the non-linearity relation of the design area of throttle holes with the design velocity, there is no any accurate and reliable method for throttle holes area design of telescopic shock absorber. In this paper, analyzed the various damping factors affecting design, it was established that the mathematics model of throttle holes area by single velocity value. Studied the method of optimal design, the target function of curve fitting optimal design for throttle holes was constructed. A practical design example of throttle holes area with this method is given, and the designed result was compared with that by single velocity, and shown on the blueprint of telescopic shock absorber manufactory. The performance test was conducted for the telescopic shock absorber developed with the new design methods in laboratory, and the test results were compared with the design target value. The experiment results show that the design method of curve fitting optimal for the area of throttle holes is correct, and the designed values are reliable.
Two new soft-switching converters for switched reluctance motor drives are proposed and analyzed. The proposed zero-voltage-transition (ZVT) converter possesses the definite advantages that both main transistors and diodes can operate with zero-voltage switching (ZVS), as well as unity device voltage and current stresses. On the other hand, the proposed zero-current-transition (ZCT) converter offers the advantages that both the main and auxiliary switches operate with zero-current switching (ZCS), as well as minimum current and voltage stresses. Both converters have the merits of simple circuit topology, minimum component count and low cost.
This paper is concerned with the development of an ultrasonic wave sensor system. A development of the sensor system a the robot which moves in the parallel to the wall is proposed. Ultrasonic wave frequency is 40 kHz. The sensor output is calculated with a PIC (computer), and it is displayed by a LCD screen. The architecture to introduce an ultrasonic wave sensor system for the moving environment is proposed. This architecture is simple, so it is applicable to measurement of the positioning control study. A sensor system was developed using only inexpensive and easily available components. Based on the information obtained while designing, manufacturing and testing the prototype, it was concluded that the system proved to be sufficiently capable for use by robots.
This paper proposes an integrated Halbach-magnetic-geared permanent-magnet (PM) motor to meet the new demands arising from electric vehicles. It can offer the advantages of lightweight, compact size and low-speed high-torque operation. The key is to newly incorporate the Halbach arrays into the coaxial magnetic gear (MG) in such a way that the PM motor field and the MG field are decoupled. In addition, because the adoption of Halbach arrays can enhance the effective harmonic components as well as suppress the useless harmonic components of the magnetic field, the torque transmission performance of the outside MG can be improved. Moreover, the iron losses can also been reduced. Simulation results based on the time-stepping finite element method are given to verify the validity of the proposal.
In this paper, we describe the global approach that has been developed at INRETS-LTE for hybrid powertrain sizing, consumption gain evaluation, and optimal control. The procedure is described in the particular case of a two clutch parallel hybrid architecture, but could apply to any other configuration. Firstly the context and the common issues related to this subject are described. Then our global approach is detailed: sizing procedure, offline global optimization process, method for obtaining suboptimal online energy management laws, and the use of these laws on the test bench. Simulation or optimization results are presented at each step of the procedure.
Lunar rovers are required to traverse rough terrains that include craters and rear cliffs, which are scientifically important locations that need to be explored. Recently, wheeled rovers have been gaining popularity for their use in conducting planetary exploration missions. However, there is a problem associated with wheeled rovers in that they are likely to get stuck in soil while traversing such terrains. In this study, we develop a new flexible wheel. This wheel can traverse soft soil. We describe an interaction model between the flexible wheel and soft soil. Then, on the basis of this model, we propose new wheel forms. In addition, to determine the traversability of the proposed wheel on the basis of slip ratio and sinkage, we perform running experiments on soil, similar to regolith.
As a novel series-parallel power train, electric variable transmission (EVT) has attracted increased interests in recent years because of its high level integration and the advantages in improving fuel economy and reducing emissions. This paper will briefly introduce this novel power train and put more emphasis on its applications in hybrid electric vehicle (HEV) including modeling, simulation and experimental study. The work is helpful to design EVT, analyze the power flows of an EVT based HEV, and make the control strategy. Energetic Macroscopic Representation (EMR) is used in the global modeling for the EVT based HEV, and a control scheme is deduced from EMR models using specific inversion rules.
An emergency-shutdown system has been developed to be mounted on the existing joystick-type electric wheelchair so that the wheelchair is halted when disabled or elderly riders make operational errors caused by strain. Operational errors are often made when pedestrians appear suddenly in front of a rider and this causes the rider to grab the joystick tight, or to tilt the joystick so hard that the stick is fully throttled. A simple system, which detects errors with a pressure-sensitive switch and operates a self-holding current-shutoff system thereafter, was developed as a system applicable to conventional, commercially-supplied electric-wheelchairs. The development results are described.
Physical activity, depending on work load as well as work environment, is modulated by Electrocardio-vascular activity. Activity of an electrocardiogram (ECG) may be associated with the physical load of moving for people with mobility handicaps in use of wheelchairs. The aim of this study is to investigate the relationship of ECG activity with the physical load of electric and manual wheelchair users and visually impaired people when crossing a main road with difficult access to high sidewalks. Eight voluntary students participated in the study. R-R interval times of heart beats were continuously recorded for each session of manual/electric wheelchairs and visually impaired. Experimental road conditions included places where there was a 0 cm to 10 cm drop or a steep step at both sides of the road. It is concluded that electric wheelchairs can provide stable driving for their users under conditions where there are differences in height between sidewalk and road, which are common obstacles for the users of wheelchairs. Furthermore, the influences of the sidewalk curb on heart beats when changing the method of transportation with difference conditions of curb are discussed. In addition, it was found that there are different influences of the curb heights on wheelchair users and visually impaired people.
As ultracapacitors are being used for many years in applications in the fields of transportation, regenerative energy and industry recently they become more and more an important component for automotive engineers. Global pressure on car manufacturers to build low or zero emission vehicles forces designers to review energy storage systems. Therefore an ultracapacitor is used because of significant advantages compared to traditional storage systems as batteries. Besides enabling to size the primary energy system only for average power needs ultracapacitors fascinate by their robustness under challenging thermal, mechanical and electrical conditions. With these characteristics they can form a highly efficient system in combination with other energy storage systems. Maxwell Technologies offers a wide range of components which match to many applications in automotive and other engineering sectors.