Refine Your Search

Topic

Author

Affiliation

Search Results

White Paper

Studies into Additive Manufacturing for In-Space Manufacturing

2017-06-26
WP-0001
NASA has embarked on an ambitious program to integrate additive manufacturing techniques and to develop processes for the microgravity environment. The most recent example of this program is the successful launch and deployment of the first 3D printer on the International Space Station. In this one-year effort, students were required to meet a series of milestones to design, manufacture, and test their ideas in close cooperation with members of the NASA Exploration Augmentation Module (EAM) concept team.The participants in this project were tasked with thinking of new solutions using AM that would simultaneously be recyclable with minimal loss in mechanical properties but also have the capacity for high mechanical properties. Working in interdisciplinary teams, the participant teams investigated the use of recycled materials, characterization, testing, modeling, and tool development.
Technical Paper

Vertical vehicle dynamics on soft ground~Investigations with FEM

2000-06-12
2000-05-0393
The Finite Element Method (FEM) has proved to be a suitable tool for the investigation of wheel-soil interaction. Compared to analytical models, the FEM presents numerous advantages. The sinkage and the deflection of the wheel, the pressure distribution in ground, the motion of the soil and especially the contact shape between the elastic wheel and the deformed soil are gained as simulation results. Moreover, the soil compaction in the depth can be visualized. Using the FEM, effects have been investigated so far with the interaction between a single wheel and soft soil. Because of the change of the ground contour due to the dynamical wheel-loads, depending on the vehicle oscillation, the influence from the pitching and vertical oscillating vehicle has to be considered. Therefore the well-known FEM-based simulation concept VENUS is extended to VENUS-DYN (DYNamic VEhicle NatUre Simulation), that includes a two-dimensional model of a complete vehicle interacting with soft ground.
Technical Paper

Mobility and fuel economy of hybrid-driven vehicles in terrain~Results from computer simulation

2000-06-12
2000-05-0394
An important requirement for the application of hybrid drives in future terrain vehicles is their competitiveness with regard to the driving properties and the fuel economy. Therefore, a two-axle, all-wheel-driven military transport vehicle equipped with a serial hybrid propulsion system has been regarded and examined by computer simulation. The tool, used for this purpose, is the simulation program ORSIS, (Off Road Systems Interactive Simulation), which has been developed at the University of the Federal Armed Forces in Hamburg. By generating a realistic surrounding area with reproducible conditions ORSIS allows an objective comparison of different vehicle types and the investigation of the influence of modified vehicle parameters. The paper presents results from computer simulations which include acceleration and braking procedures, determination of maximum drawbar pull, and the estimation of fuel consumption under realistic conditions by driving on determined routes.
Technical Paper

Relative motion estimation using radar and vision data integration

2000-06-12
2000-05-0379
A radar sensor is an essential part for forward collision warning and avoidance. The radar sensor gives information of relative distance and speed. However, some lane change situations need additional sensors for reliable estimation of relative motion. So, the authors introduce a vision system that can detect interruption by lane changing and give approximate relative distance. Vision data are used to verify radar data, and vision/radar data are used for more accurate estimation of relative motion. The authors perform a vehicle test for the verification of this algorithm.
Technical Paper

A Modeling of the Heart Rate Variability to Estimate Mental Work Load of Driver

2000-06-12
2000-05-0375
When we evaluate the human-machine-environment systems, it is very important to consider not only the performance of the machine system but also the Mental Work Load (MWL) for the operator. Because human being have a high adaptability to their surroundings. Therefore, we constructed the dynamic model of the human-machine-environment system using the Heart Rate Variability.
Technical Paper

Driver → vehicle behavior → intelligent vehicle

2000-06-12
2000-05-0377
In this article, the authors try to get their own contribution for solving any actual problems in vehicle stability and handling framework. It used submodeling techniques for entire dynamic mechanical system. Fuzzy modeling is used for one realistic description of dynamic mechanical system represented by vehicle. It applied one solving algorithm of fuzzy relational equations, having genetics algorithm support technique. Finally, it construct one neural network will be fast learning from relations equations solutions. The online work is required approximate equal with driver behavior.
Technical Paper

ADM A NEW DRIVE-TRAIN MANAGEMENT

2000-06-12
2000-05-0389
The new drive-train system Automatic Drive-Train Management (ADM) controls all traction systems present in a vehicle. Applications include the all wheel drive feature in transfer cases and differential locks in axles. Compared to manually operated or automated traction control systems ADM has the advantage of transferring 100 percent of the torque automatically. The range of application for the ADM system would be a 4×2 truck tractor to a 6×6 off-road vehicle. A key feature of the ADM system is the synchronized engagement of gears in a two-speed transfer case while the vehicle is moving.
Technical Paper

A forward collision warning an avoidance algorithm

2000-06-12
2000-05-0366
The number of automobiles is rapidly increasing, as are the importance of the car as a way of transportation, and the variety of its uses. In these environments, a safety, one of the primary factors, which must be considered in automotive engineering, demands a system that aids the driver''s perception, in addition to the existing passive method, which relies on just man''s ability. In this point of view, development of the promoted system that complements the passive safety devices is demanded. A system like this should make driving safe and satisfy the need for comfort, while decreasing the driver''s burden and fatigue. The object of this paper is the development of an algorithm that warns the collision ahead and avoids this situation, using some information about the host-car, target-car, surroundings, road conditions, etc. The warning system is developed using a decision algorithm of the degree of safety. To show the validity system based on our safety algorithm.
Technical Paper

A multi-vehicle platoon simulator

2000-06-12
2000-05-0363
This paper presents a real-time vehicle powertrain simulator and a pseudo real-time multi-vehicle platoon simulator. The developed powertrain simulator simulates the complex vehicle powertrain dynamics, including detailed shifting transients, in the PC environment in real time. The driver input is provided using a throttle pedal interfaced using the game port. The processor requirements vary depending on the simulation options selected. In the basic version, this requirement is only approximately 20% of a 300 MHz Pentium II- based PC. For multi-vehicle platoon simulation, a network configuration is proposed. It links several individual powertrain simulations via the TCP/IP network. This network platoon simulation is also linked to a server which graphically displays the multi-vehicle platoon operation. In this network configuration, due to a random delay in data transfer the simulation time kernel is made to lag real time.
Technical Paper

A throttle/brake control law for vehicle intelligent cruise control

2000-06-12
2000-05-0369
A throttle/brake control law for the intelligent cruise control (ICC) system has been proposed in this paper. The ICC system consists of a vehicle detection sensor, a controller and throttle/brake actuators. For the control of a throttle/brake system, we introduced a solenoid-valve-controlled electronic vacuum booster (EVB) and a step-motor-controlled throttle actuator. Nonlinear computer model for the electronic vacuum booster has been developed and the simulations were performed using a complete nonlinear vehicle model. The proposed control law in this paper consists of an algorithm that generates the desired acceleration/deceleration profile in an ICC situation, a throttle/brake switching logic and a throttle and brake control algorithm based on vehicle dynamics. The control performance has been investigated through computer simulations and experiments.
Technical Paper

Total networked truck driver information and multiplexing vehicle area networks

2000-06-12
2000-05-0372
The truck market is more and more demand driven and complexity has grown substantially. Especially in combination with sophisticated bodies and trailers flexible electronic solutions are required to cope with this complexity. A new approach to meet these demands is to use standardized PLC functionality for vehicle multiplexing and visualization electronics. The VDO KIBES Mk II system is such a solution especially designed for the commercial vehicle market. With software-controlled modules replacing hardwired control centers the vehicles can be easily differentiated at the latest possible time. For the traffic information terminals the first devices are modern radios. Besides classical traffic news the RDS/TMC system delivers continuous digital information for the chosen area. Alternatively telematic service providers can transmit trip-individual traffic and weather information, e.g., through GSM mobile phones.
Technical Paper

Lateral and longitudinal control algorithms for visual platooning of autonomous vehicles

2000-06-12
2000-05-0373
This paper describes lateral and longitudinal control algorithms when vision-based autonomous vehicles form a platoon by detecting a preceding one with a machine vision system. The visual platooning is an extension of the longitudinal control in ACC, and is featured by both the lateral and longitudinal control of following vehicles. The lateral control algorithm for a following vehicle uses a target point positioned on a preceding vehicle and captured in the field of view. When the target point is appropriately positioned, a following vehicle is guided as if it chased the target. The origin of the lateral control algorithm is an algorithm for an automated vehicle with a localization function including the dead reckoning, named the target point following algorithm. The lateral control in the visual platooning consists of the steps of target point detection, path generation, and lateral control calculation.
Technical Paper

Development of cabin air filter with aldehyde capture function

2000-06-12
2000-05-0343
Aldehydes are the cause of sick house syndrome or chemical sensitivity and have harmful influences for human beings. In the cabin of vehicle, aldehydes which are included in the volatilization gas from the interior materials, DE emission gas in intake air, cigarette smoke and so on spoil the comfortableness. Active carbon, which has been used as an adsorbent, shows an excellent removal efficiency for most of the gas components by physical adsorption. But for aldehydes, it has difficulty because aldehydes are hard to be adsorbed physically. We have developed new aldehydes adsorbent undergoing addition reaction with gaseous aldehydes on its surface. Aldehydes capture material (ACM) make use of the chemical reaction using a resorcin as a reagent and an H-type zeolite as a water-containing support, and active hydrogen is used as a catalyst to promote the reaction. In addition, we have applied ACM to cabin air filter (CAF) of vehicle.
Technical Paper

Computational design of commercial vehicle for reconciling aerodynamics and engine cooling performance

2000-06-12
2000-05-0344
As the global environmental protection becomes the world consensus recently, the regulations of the fuel consumption and the exhaust gas have large effects on the performance and the fundamental structure of commercial vehicles. Especially the technology concerning "fluid" and "heat" has a close relationship with those issues. Owing to above circumstances, commercial vehicles such as large trucks and buses are forced to be designed near the limit of allowance. Furthermore, a rapid design is another requirement. However, though significant number of variations, i.e., cab configuration, wheel base, rear body configuration, engine specification, etc., are prepared, it is impossible to improve the performance of all those combinations by experiments which cost a lot. Accordingly, the quantitative prediction using computer will become indispensable at the beginning term of new car development.
Technical Paper

CAD of engine dynamic test bed based on hybrid simulation

2000-06-12
2000-05-0348
The hybrid simulation method is adopted to develop engine dynamic test bed based on eddy-current dynamometer. The hybrid simulation scheme of engine dynamic test bed is designed. The principle is discussed. Finally, the CAD method is used to design main parameters of engine dynamic test bed based on simulation ECE15 and US LA4-CH Driving Schedules by Shanghai Santana 2000 car. The results are compared to the actual test results on the chassis dynamometer. The hybrid simulation method is proved to be an efficient way by simulation and comparison.
Technical Paper

Application of feedforward controller on a four-wheel-steering car: The concept

2000-06-12
2000-05-0352
In this paper will be presented an alternative of feedforward controller (FFC) system to overcome four-wheel-steering weaknesses. The system estimates vehicle output parameters that consists of lateral acceleration (v), roll rate (ϑ) and yaw rate (φ) as well as the correct input parameters of vehicle that consists of longitudinal sped (Uo) and steering wheel (δsw). To estimate vehicle output parameters used will be full car mathematical model. The estimated vehicle output parameters together with given vehicle input parameters are used to estimate understeer coefficient (Ku). Finally, it will be used to compute the correct vehicle input parameters required by the 4WS system.
Technical Paper

Truck recycling: Environmental-friendly guidelines

2000-06-12
2000-05-0357
Transport is a fundamental aspect of community prosperity and it is closely connected to its development. Transport plays an essential role among the production cycles of a nation, and the commercial vehicle (trucks or buses) makes it possible to become true. From the days when commercial vehicles first appeared, to the early ''80s, main research themes were those intended to increase "productivity" and "profitability." In the ''80s a new and common ecological awareness had induced the industrial sector, and specially motor vehicle manufacturers to try reducing atmosphere and water pollution effects as much as possible. Starting with the ''80s, new needs have appeared in addition to the "usual" ones, entailing entirely new research trends for commercial vehicles.
Technical Paper

The development of warm-up control strategies for a methanol reformer fuel cell vehicle

2000-06-12
2000-05-0330
A fuel-cell-powered vehicle requires a plentiful supply of hydrogen to achieve good performance. This can be produced from methanol via an on-board reformer and gas clean-up unit. Since the reformer can take several minutes to reach its operating temperature, it is initially necessary to provide an alternative power source, such as a battery or ultra-capacitor, in order to drive the vehicle. This paper describes the use of a fuel cell vehicle simulation to predict behavior over a drive cycle from a cold start and to evaluate different warm-up control strategies in terms of performance and fuel efficiency.
Technical Paper

Comparison of Disc and Drum Brake Rotor Mode Movement

2000-06-12
2000-05-0338
Disc brake noise is generally accompanied by a movement of the rotor mode of vibration. It is shown that the speed of mode movement is related to the frequency of noise generation divided by the rotor vibration mode order, the direction being the same as disc rotation. The same type of movement is also seen in a drum brake generating low frequency noise. The backplate is shown to have a moving mode with a speed that is twice the noise frequency divided by the mode order. A possible drum mode is indicated and it is suggested that this rotates at the frequency of noise and in the direction of drum rotation. It is proposed that the mechanism involved with disc mode movement and drum/backplate mode movement may have a common explanation. It is explained that this mode movement is the result of two contra-rotating waveforms of differing amplitudes - this being an explanation for both brake types as a feature of brake noise.
Technical Paper

The Application of the Simulation Techniques to Reduce the Noise and Vibration in Vehicle Development

2000-06-12
2000-05-0337
An overview of the analytical noise and vibration simulations performed to support the design and development of the passenger car was presented. Analytical models of the structural vehicle and acoustic cavity were developed, and several simulations related to the NVH were performed in the prototype development stage. All of the simulations were performed to minimize development time as well as to optimize the cost, weight, and performance of the NVH and the maximum frequency of these analyses is 200 Hz. The modal analysis and design sensitivity analysis of the body-in-white was performed to minimize the mass while maintaining the body stiffness by using the concept model and detailed model. Most of the subsystems such as engine mount, steering, suspension and exhaust pipe system were analyzed respectively and in the combined system for the design studies of the idle shake and high-speed wheel shake analysis.
X