• 한국자동차공학회논문집
• /
• 제15권1호
• /
• pp.125-132
• /
• 2007

Within the framework of brake-by-wire technology, this paper presents five types of novel models of electro-mechanical disk brake calipers with self-servo mechanism which provides self-servo effect of boosting a friction force generated between the brake pad and the rotor disk surface. The models have been developed utilizing patent map analysis results of previous invents of electro-mechanical brake calipers. The feasibility of the developed motor-driven brake caliper models have been validated through the dynamic simulation analysis. Among the developed models, the caliper mechanism with separated pressure plate was designed especially in detail and was made as a pilot. The pilot caliper has been installed on the simple test bed constructed with domestic passenger car brake components, and its function and effectiveness have been validated through several types of experimental tests.

• 한국자동차공학회논문집
• /
• 제20권6호
• /
• pp.33-38
• /
• 2012

EMB is considered as the next generation braking mechanism because it has simple structure and is environment friendly. However, as other brake mechanisms, EMB should be operated reliably for any operating conditions. EMB should be designed with fail-safe and fault-tolerant control concepts which require robust fault detection algorithms for various possible faults. In the design of fault detection algorithms, it is very difficult to construct faulty conditions in real EMB and thus, simulations are often used to emulate the faulty conditions. In this paper, a simulation tool is developed using the commercial software to emulate gear faults in the EMB mechanism. A backlash compensation algorithm is introduced based on contact point detection because screw backlash causes a delay in clamping force response time.

• 제어로봇시스템학회논문지
• /
• 제17권11호
• /
• pp.1145-1153
• /
• 2011

EMB (Electro-Mechanical Brake) systems can provide improved braking and stability functions such as ABS, EBD, TCS, ESC, BA, ACC, etc. For the implementation of the EMB systems, reliable and robust fault detection algorithm is required. In this study, a model-based fault detection algorithm is designed based on the analytical redundancy method in order to monitor current and force sensor faults in EMB systems. A state-space model for the EMB is derived including faulty signals. The fault diagnosis algorithm is constructed using the analytical redundancy method. Observer is designed for the EMB and the fault detectability condition is examined based on the residual analysis. The performance of the proposed model-based fault detection algorithm is verified in simulations. The effectiveness of the proposed algorithm is demonstrated in various faulty cases.

• Tribology and Lubricants
• /
• 제34권2호
• /
• pp.55-59
• /
• 2018

This paper proposes a new type of electro-mechanical wedge brake for commercial vehicles. The brake operates on a novel mechanism for self-boosting braking friction forces using eccentric shafts, and involves wedges that are inserted between the rampbridge and traverse; this self-boosting mechanism is explained herein. A dynamic analysis using ADAMS was conducted, and the findings are reported. The constraint and contact conditions are explained to verify the precision of the dynamic analysis. The dynamic analysis shows that in the proposed mechanism, the self-boosting effect occurs as desired. However, it is also noted that the system has a limitation in terms of the production of unlimited braking forces that can jam the roller inside the wedges. After demonstrating the self-boosting effect, dynamic analyses are performed for several values of the wedge angles and friction coefficients between the brake pads and disks. Conventionally, a lower wedge angle has been suggested owing to its provision of a larger clamping force for given friction coefficients. However, it is noted that lower wedge angles can lead to a higher probability of occurrence of undesirable high braking forces, which can jam the roller into the wedge; thus, a larger wedge angle is preferable for avoiding the undesirable jamming phenomena. These analysis results are presented and discussed herein.

• 한국정밀공학회지
• /
• 제12권7호
• /
• pp.123-130
• /
• 1995

This study presents model synthesis and performance investigation of a new brake system using electro-rheological(ER) fluids. Field-dependent Bingham properties characterized by non-zero yield stresses of the ER fluids are experimentally distilled. These properties are then incorporated with the governing equation of the proposed brake system which features design simplicity, fast response and salient controllability. After analyzing system performance with respect to design parameters such as electrode gap and length, an appropriate size of the brake is designed and fabricated. Both simulation and experimental works are undertaken in order to determine the feasibility and efficiency of the proposed brake system. The system performances are justified by evaluating field-dependent braking torques as well as braking times.

• 한국정밀공학회지
• /
• 제13권8호
• /
• pp.102-111
• /
• 1996

This paper presents a proof-of-concept investigation on an active tension control using an ER (electro-rheological) brake actuator. Firstly, an ERF (electro-rheological fluid) which has an inherent reversible feature from Newtonian fluid to Bingham fluid upon applying an electric field is composed, and its property is tested to obtain intrinsic parameters of the Bingham model. An appropriate size of the ER brake is manufactured on the basis of the Bingham model, and dynamic characteristics of the brake are experimentally identified. After formulating a governing equation of motion of the tension control system, a sliding mode controller is designed to achieve a certain desired level of tension. Both simulation and experimental works are undertaken in order to demonstrate the efficiency and feasibility of the proposed active tension control method.

• 한국산업융합학회 논문집
• /
• 제20권4호
• /
• pp.313-323
• /
• 2017

As vehicles become more intelligent this is focused on ways to enhance safety and convenience for both drivers and passengers. In particular, x-by-wire systems that replace rigid mechanical components with dynamically configurable electronic elements are being developed to expand intelligent functions, such as adaptive cruise control or lane departure warning system. Because the malfunction of safety-related modules controlling critical functions, such as brakes, throttle, and steering in x-by-wire systems, can cause injury or death, safety and reliability are the most critical issue for automotive vendors and parts manufacturers. In an effort to develop better and effective brake-by-wire system, this paper presents EMB system by using the low speed electric vehicle, which is not required large braking force, with motor controller. In addition, we design performance evaluation system of EMB with 1/4 low speed electric vehicle model and suggested EMB is evaluated through the performance evaluation system.

• 한국정밀공학회지
• /
• 제33권7호
• /
• pp.535-540
• /
• 2016

The braking device in railway vehicles decelerates or stops the train by dissipating the thermal energy converted from kinetic energy into the air. Therefore, the brake system is crucial for safety. In this paper, we performed a study on an electromechanical brake actuator using an electrical motor as an alternative to pneumatic air cylinders to reduce the idle running time in braking, which subsequently increases braking distance, and to ensure reliable response characteristics. Especially, to analyze the response characteristics of the electromechanical brake actuator, we measure the delay time, response time and power consumption compared to the air cylinder. It is confirmed that the electromechanical brake actuator can reduce reaction time by 0.1 seconds (Braking Action) and 0.46 seconds (Brake Release) compared to the air cylinder.

• 한국자동차공학회논문집
• /
• 제16권4호
• /
• pp.173-178
• /
• 2008

Electro-hydraulic brake system has many advantages. It provides improved braking performance and stability functions. It also removes complex mechanical parts for freedom of design, improves maintenance requirements and reduces unit weight. However, the EHB system should be dependable and have back-up redundancy in case of a failure. In this paper, the model-based fault diagnosis system is developed to monitor the brake status using the analytical redundancy method. The performance of the model-based fault diagnosis system is verified in real-time simulation. It demonstrates the effectiveness of the proposed system in various faulty cases.

• 한국산학기술학회논문지
• /
• 제21권10호
• /
• pp.581-588
• /
• 2020

본 논문은 전기기계식제동장치(EMB : Electro Mechanical Brake, 이하 EMB)의 제동패드 마모발생에 따른 소프트웨어 기반의 마모보상방법의 적용 및 성능평가를 다루었다. EMB의 구동을 위해 사용된 모터는 3상 매입형 영구자석 동기전동기(IPMSM : Interior Permanent Magnet Synchronous Motor, 이하 IPMSM)가 사용되었다. EMB의 압부력(clamping force) 제어를 위해 위치제어기, 속도제어기 및 전류제어기가 적용되었으며, IPMSM의 출력 압부력 예측을 위해 모터의 거리별 압부력 실험을 통하여 힘 추정기(force estimator)를 1차 모델식으로 단순화 하였다. 제동패드에서 마모가 발생함에 따라 IPMSM에서 출력되는 토크전류의 크기가 감소하는 특성을 이용하여 기준 토크전류와의 비교를 통해 힘 추정기를 업데이트하는 방법으로 마모보상이 가능함을 보였다. 제동패드의 마모 후 최대 압부력 도달시간이 0.1초 이내로 증가하였으나, 마모패드 장착시에도 제동압부력은 마모 전 제동패드와 동일한 최대 기준 압부력을 만족하였으며, 최대압부력 도달시간의 경우 0.5초(기준값) 이내임을 실험으로 검증하였다. 소프트웨어 기반의 EMB 제동패드의 마모보상 방법은 철도차량의 출발 전 제동장치 점검시 테스트모드의 진입을 통하여 수행이 가능하다.