• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.6
• /
• pp.234-240
• /
• 2002

This paper treats the problem of estimating the longitudinal velocity of a braking vehicle using measurements from an accelerometer and wheel speed data from standard anti-lock braking wheel speed sensors. We develop and experimentally test three velocity estimation algorithms of increasing complexity. The algorithm that works the best gives peak errors of less than 3 percent even when the accelerometer signal is significantly biased.

• International Journal of Automotive Technology
• /
• v.7 no.4
• /
• pp.449-457
• /
• 2006

The driver model during drift cornering was examined, and a technique to improve vehicle movement performance during drift cornering was investigated. Based on the results obtained, the driver was found to steer using feedback of the body slip angle and the body slip angle velocity during drift cornering. Moreover, improvement of the cornering force characteristic, at which exceeded the maximum cornering force calm as much as possible is important.

• Journal of Institute of Control, Robotics and Systems
• /
• v.21 no.4
• /
• pp.372-377
• /
• 2015

In this paper, the consideration factors that affect the actual driving of a rover wheel was examined based on the wheel-terrain model. For the evaluation of driving performance in a real environment, the test bed of the rover wheel consists of the driving part of the wheel and sensing part of the various parameters was designed and assembled. Using the test bed, the preliminary driving experiment concerning the slip ratio, sinkage, and friction force according to the rotational velocity and the shape of the wheel were carried out and evaluated. The wheel test bed and the experiment results are expected to contribute to finding the optimal result in the designing of the wheel shape and the planning of the driving conditions through further study.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.05a
• /
• pp.103-108
• /
• 2007

This paper presents a friction model to realize self-excited vibration of multi-body systems. The friction coefficient is modeled with a spline function in most commercial codes. Even if such a function resolves the problem of discontinuity in friction force, it cannot realize self-excited vibration phenomena. Furthermore, as the relative velocity approaches zero, the friction coefficient approaches zero with the conventional model. So, slip occurs when small force is applied to the system. To avoid these problems a new friction model is proposed in this study. With the new friction model, the self-excited vibration can be realized since the friction coefficient changes with the relative velocity. Furthermore, the slip phenomena could be reduced significantly with the proposed model.

• 제어로봇시스템학회:학술대회논문집
• /
• 1991.10a
• /
• pp.783-786
• /
• 1991

Generally, The position of mobile robot moving on the plane is measured by the method of dead reckoning, using the encoder system coupled on a wheel axis. But it is noted that the encoder system cannot check the slip of a wheel, often occurring in tracking of the mobile robot. In this study, using velocity angular velocity sensor with a tuning fork vibration system, the system is developed which can measure the directional angle of positional variables on the mobile robot. By measuring the variations of tracking direction mobile robot equipped with this system, following result is found; In spite of the slip at a wheel when measuring the tracking directional angle, the error occurs in the range of .+-. 1 (degree).

• 한국전산유체공학회:학술대회논문집
• /
• 2004.10a
• /
• pp.79-82
• /
• 2004

As an alternative numerical method, the lattice Boltzmann method (LBM) is used to simulate a 2-dimensional pressure driven microchannel flow which comes from frequently in MEMS problems. The flow is assumed to be isothermal ideal gas flow. The flow field is calculated with various Knudsen numbers, pressure ratios and aspect ratios of the microchannel. The LBM can show the fundamental characteristics in microchannel flow such as velocity slip and nonlinear pressure drop.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.13 no.5
• /
• pp.195-201
• /
• 2005

In conventional Vehicle Stability Control (VSC) System, a control threshold is designed by average driver characteristics. Despite the stabilizing effort, VSC causes redundancy to an expert driver. An advanced VSC which has flexibility on its control property is proposed in this study. By using lateral velocity estimator, a control threshold is determined on side slip angle and angular velocity phase plane. Vehicle planar motion model based sliding controller is modified with respect to various control thresholds. The performance of the proposed VSC algorithm has been investigated by human-in-the-loop simulation using a vehicle simulator. The simulation results show that the control threshold has to be determined with respect to the driver steering characteristics. A VSC with variable control thresholds would provide an improvement compared to a VSC with a constant threshold.

• Proceedings of the KSME Conference
• /
• 2001.06b
• /
• pp.565-570
• /
• 2001

Vehicle dynamics control (VDC) system requires more information on driving conditions compared with ABS and/or TCS. In order to develop the VDC system, tire slip angles, vehicle side-slip angle, and vehicle lateral velocity as well as road friction coefficient are needed. Since there are not any cheap and reliable sensors, recent researches on parameter estimation have given rise to a number of parameter estimation techniques. This paper presents new vehicle model to estimate vehicle's yaw rate. This model is improved from the conventional 2 degrees of freedom vehicle model, so-called bicycle model, taking nonlinear effects into account. These nonlinear effects are: (i) tyre nonlinearity; (ii) lateral load transfer during cornering; (iii) variable gear ratio with respect to vehicle velocity. Estimation results are validated with the experimental results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.11a
• /
• pp.596-599
• /
• 2004

The media transport systems, such as printers, copiers, facsimile, ATMs, cameras, etc., have been widely used and being developed rapidly. In the development of those systems, the media feeding mechanism is an important key technology for the design and development of the media transport systems. In this paper, a multi-degree of freedom sheet model with dynamic contact conditions is presented to understand the mechanism of sticking and jamming. A sheet is modelled as a cantilever beam and the feeding velocity is assumed to be constant. The relation between the feeding velocity and the coefficient of friction for guaranteeing stable feeding is presented. Simulations are performed for a horizontal linear guide and a oblique linear guide, calculating the contact force and contact states of mass points.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.17 no.6 s.123
• /
• pp.524-530
• /
• 2007

This paper presents a friction model to realize self-excited vibration of multi-body systems. The friction coefficient is modeled with a spline function in most commercial codes. Even if such a function resolves the problem of discontinuity in friction force, it cannot realize self-excited vibration phenomena. Furthermore, as the relative velocity approaches zero, the friction coefficient approaches zero with the conventional model. So, slip occurs when small force is applied to the system. To avoid these problems a new friction model is proposed in this study. With the new friction model, the self-excited vibration can be realized since the friction coefficient changes with the relative velocity. Furthermore, the slip phenomena could be reduced significantly with the proposed model.