• 한국항해항만학회지
• /
• 제28권3호
• /
• pp.227-232
• /
• 2004

차량동역학제어시스템은 복잡하고 비선형이므로 잠금방지 제동시스템 및 자동주행시스템 개발에 어려움이 있다. 차량절대속도를 추정하기 위해 퍼지 로직 기법이 최근 적용되어 정상적인 조건에서 만족할 만한 결과를 얻고 있다. 그러나 급격한 제동시 추정오차가 크게 발생되었다. 본 논문에서는 휠 속도 센서를 이용하여 무인 컨테이너 운송차량의 절대속도를 추정하기 위해, 뉴럴 네트워크 모델의 방사대칭 기저함수와 주성분 분석법을 적용하여 10개의 추정 알고리즘중 오차를 4％ 이내로 추정할 수 있는 알고리즘을 제시하였다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 춘계학술대회
• /
• pp.519-524
• /
• 2004

This study is concerned with the braking distance estimation using frictional energy rate. First, steady state rolling analysis is performed, and using this result, the braking distance is estimated. Dynamic rolling analysis during entire braking time period is impratical, so that this study divides the vehicle velocity by 10km/h to reduce the analysis time. The multiplication of the slip rate and the shear stress provides the frictional energy rate. Using frictional energy rate, total braking distance is estimated, In addition, ABS(Anti-lock Brake System) is considered, and two type of slip ratios are compared, One is 15% slip ratio for the ABS condition, and the other is 100% slip ratio which leads lo the almost same braking distance as the elementary kinematic theory. A slip ratio is controlled by angular velocity in ABAQUS/Explicit, A 15% slip ratio gives the real vehicle's braking distance when the frictional energy occurred al disk pad is included. Disk pad's frictional energy rate is calculated by the theoretical approach.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집B
• /
• pp.676-681
• /
• 2001

ABS is a safety device, which adds hydraulic system to the existing brake system to prevent wheel from locking, so we can obtain maximum braking force on driving. The hydraulic system to control braking pressure consists of sol-flow type using solenoid valve, flow control valve or consists of sol-sol type using two solenoid valve. In this paper, the hydraulic system in ABS is composed of sol type using a 3port-2position solenoid valve, and vehicle system is composed of 1/4 vehicle model. And slip ratio is controlled using PWM (Pulse-Width-Modulation) control algorithm. Braking friction coefficient and tracking friction coefficient which are described by slip ratio's function have maximum value when slip ratio has its value from 0.1 to 0.3. And slip ratio is controlled constantly in this boundary value even in the variation of road's condition in some boundary.

• International Journal of Automotive Technology
• /
• 제6권1호
• /
• pp.37-44
• /
• 2005

The creation of automotive systems of active safety with intelligent functions needs the use of new control principles for the wheel and automobile. One of such directions is the pre-extreme control strategy. Its aim is the ensuring of wheel's work in pre-extreme, stable area of tire grip wheel slip dependence. The simplest realization of pre-extreme control in automotive anti-lock brake systems consists in the threshold and gradient algorithms. A comparative analysis of these algorithms, which has been made on 'hardware in-the-loop' simulation results of the braking for bus with various anti-lock brake systems (ABS), indicated their high efficiency.

• Smart Structures and Systems
• /
• 제8권5호
• /
• pp.501-524
• /
• 2011

Recent studies have discovered that a conventional passive isolation system may suffer from an excessive isolator displacement when subjected to a near-fault earthquake that usually has a long-period velocity pulse waveform. Semi-active isolation using variable friction dampers (VFD), which requires a suitable control law, may provide a solution to this problem. To control the VFD in a semi-active isolation system more efficiently, this paper investigates experimentally the possible use of a control law whose control logic is similar to that of the anti-lock braking systems (ABS) widely used in the automobile industry. This ABS-type controller has the advantages of being simple and easily implemented, because it only requires the measurement of the isolation-layer velocity and does not require system modeling for gain design. Most importantly, it does not interfere with the isolation period, which usually decides the isolation efficiency. In order to verify its feasibility and effectiveness, the ABS-type controller was implemented on a variable-friction isolation system whose slip force is regulated by an embedded piezoelectric actuator, and a seismic simulation test was conducted for this isolation system. The experimental results demonstrate that, as compared to a passive isolation system with various levels of added damping, the semi-active isolation system using the ABS-type controller has the better overall performance when both the far-field and the near-fault earthquakes with different PGA levels are considered.

• 한국기계가공학회지
• /
• 제5권3호
• /
• pp.71-79
• /
• 2006

ABS is a safety device for preventing wheel locking in a sudden baking. Its control methods are classified into three types; deceleration control, wheel slip control and deceleration/acceleration control. The braking force takes the influence of the friction coefficient between road and tire, which in turn depends on the wheel slip as well as road conditions. In this paper, it has been proposed the wheel slip control system to apply the adaptive control method at the ABS. To maintain wheel slip to desired wheel slip, it have been done the linearization and designed the adaptive controller to apply gradient method based on the reference model. It is illustrated by computer simulations that the proposed control system gives good performances and adaptation to parameter variation.

• 자동차안전학회지
• /
• 제16권1호
• /
• pp.21-28
• /
• 2024

Many global car manufacturers in the world are recently developing a variety of electric vehicles in response to demanding market needs. Also, they have adapted the architecture method in order to develop electric vehicles effectively. It is because architecture method can produce various electric vehicles with high profitability. However, when electric vehicles are being developed, brake system has a lot of demanding tasks in relation to deciding specification of brake system because of heavy vehicle weight, narrow power electric room space and large volume of electric hydraulic booster. In this paper, a new approach is proposed for deciding the front and rear brake systems in order to design the brake system of electric vehicles effectively. To do this, we study correlations among vehicle weight, layout of power electric room and volume of electric hydraulic booster. And then, we also study combination of hydraulic braking and regenerative braking which is widely applied to electric vehicles. Finally, we want to contribute to build up modular design of brake system for architecture of electric vehicles through these studies.

• 대한기계학회논문집A
• /
• 제30권12호
• /
• pp.1551-1556
• /
• 2006

Two yaw motion control systems that improve a vehicle lateral stability are proposed in this study: a rear wheel steering yaw motion controller (SESP) and an enhanced rear wheel steering yaw motion controller (ESESP). A SESP controls the rear wheels, while an ESESP steers the rear wheels and front outer wheel to allow the yaw rate to track the reference yaw rate. A 15 degree-of-freedom vehicle model, simplified steering system model, and driver model are used to evaluate the proposed SESP and ESESP. A robust anti-lock braking system (ABS) controller is also designed and developed. The performance of the SESP and ESESP are evaluated under various road conditions and driving inputs. They reduce the slip angle when braking and steering inputs are applied simultaneously, thereby increasing the controllability and stability of the vehicle on slippery roads.

• 한국자동차공학회논문집
• /
• 제18권2호
• /
• pp.14-23
• /
• 2010

This paper analyzes braking performance of ABS with Sliding Mode Controller, which is designed in this research and compared with that of a commercial ABS-ECU only. HILS system for this paper has an existing hydraulic brake line with an ECU of commercial passenger vehicle and it is designed to be cooperated with Sliding Mode Controller and hydraulic line. This paper shows the simulation results to meet the target slip ratio on the various road conditions and displays the performance with Sliding Mode Controller has an improvement than a commercial ABS.

• 한국자동차공학회논문집
• /
• 제15권6호
• /
• pp.120-127
• /
• 2007

This paper describes the development of a nonlinear observer for four wheel steer (4WS) vehicle. An observer is designed to estimate the vehicle variables difficult to measure directly. A brake yaw motion controller (BYMC), which uses a PID control method, is also proposed for controlling the brake pressure of the rear and inner wheels to enhance lateral stability. It induces the yaw rate to track the reference yaw rate, and it reduces a slip angle on a slippery road. The braking and steering performances of the anti-lock brake system (ABS) and BYMC are evaluated for various driving conditions, including straight, J-turn, and sinusoidal maneuvers. The simulation results show that developed ABS reduces the stopping distance and increases the longitudinal stability. The observer estimates velocity, slip angle, and yaw rate of 4WS vehicle very well. The results also reveal that the BYMC improves vehicle lateral stability and controllability when various steering inputs are applied.