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Recently steering technology focuses on not only driver's convenience, fuel efficiency, environment friendliness but also improved vehicle stability. Therefore Active Front Steering (AFS) has been widely studied as latest technical trend in steering system. This system can enhance vehicle stability by making additional road wheel angle (called ‘superimposed angle’) based on the vehicle state information such as vehicle speed, steering angle, yaw rate and lateral acceleration. While occurring superimposed steering angle, driver may feel the reaction torque which is caused from abnormal changes of steering effort with AFS mechanism installed. To solve this problem it is required to reduce steering output load in case of superimposed steering by increasing steering assist of rack assist type electric power steering. This paper describes the control method that is compensated reaction torque. And its effect of compensation is validated from test results

Good road feel means that the driver can interpret road conditions through the steering wheel. This is one of the most important requirements demanded by car makers. However, over-sensitivity in steering transmission could cause inconvenience to the driver especially maneuvering on rough roads and hence must be isolated by the steering system or by other means. To overcome this, firstly we have to distinguish diverse road conditions and apply appropriate control strategy. In this paper we've proposed two control strategies to enhance steering performance on rough roads. The first method analyzes motor position signal of Electric Power Steering (or EPS) where the road roughness is separated from the motor position signal through signal processing. The roughness then is compensated for by using EPS to obtain a better steering feel. The second method utilizes CAN transferred vehicle information from Continuous Damping Control system (or CDC).

Because of an increasing popularity of the SUV and Light Truck with an elevated center of gravity, the rollover propensity is higher than before. This paper proposes a method to detect and prevent an impending rollover of the vehicle using Electronic Stability Control(ESC). The Rollover Prevention(ROP) function determines a rollover critical situations based on the rollover propensity index and generates a proper activation through a brake and engine intervention. The rollover propensity index is calculated from the relative distance of the trajectory to the threshold on the phase plane of roll-angle and roll-rate. The threshold on the phase plane is deduced from the conservation of energy in the roll model. For the detection and activation of continuous rollover phenomena, we use the TTL concept that presents a gradually increasing rollover propensity. The proposed algorithm in this paper is shown to be effective in mitigating a rollover through the simulation and vehicle test.

Vehicle stability control system can enhance the vehicle stability and handling in emergency situation through the control of traction and braking forces at the individual wheels. In order to achieve the desired performance, we must exactly calculate compensated yaw moment, and control the wheel slip rate to generate braking force. However, the yaw moment is highly dependent on the status of tire dynamics at each wheel. In this study, we propose optimal yaw moment distribution controller based on tire model according to the normal forces, the road condition, the slip rate and the slip angle to cope with nonlinear tire dynamics. The proposed controller for distributing the desired tire slip rate makes used of the optimization technique based on the tire nonlinear model. It minimizes the braking control force corresponding to the desired tire slip at each wheel.

Measuring side forces on the automotive suspension strut damper is critical in assuring the satisfaction of the design criteria. The advanced modeling and analysis technology has been used to design and validate the side force characteristics of the strut dampers, but the experimental verification method has not been sufficiently developed. The application of the strain gages on the reservoir tube of the strut damper has been used to measure the side forces. This conventional method features that the reservoir tube of the strut damper being used as the sensing element. However, the reservoir tube of the strut damper is in the path of the various external loads, and the strain output of the reservoir tube is affected by the unwanted source of forces. A method of the direct measurement of the side forces exactly on the force application point has been developed.

This paper describes our verification work for multi-axes sensing MEMS accelerometers of comb shaped structure for electronic stability control (ESC) system. The results of basic, environmental performance test and durability test using simulation, it proved that comb structure has same performance and durability with cantilever structure. And we can also find there is no difference between single axis and multi-axes sensing accelerometer’s performance. The multi-axes sensing MEMS accelerometers of comb structure can reduce costs and increase the space efficiency of the advanced ESC system

An actual trend in the automotive industry is to have global products in order to have economy of scale. This paper presents how a Belt Drive Rack EPS developed for the North American market had to be modified in order to be assembled in a Vehicle sold all around the world. Main technical challenges for achieving that goal were generated from different Architectures, whether electrical or mechanical, used in each vehicle, Packaging issues and Regional Requirements. Main features affected are Database Configuration, Electromagnetic Compatibility, Smooth Road Shake mitigation and Pull Compensation.

With the spread of new trends such as autonomous driving and vehicle subscription service, drivers may pay less attention to the maintenance of the vehicle. Brake pads being safety critical components, the wear condition of all service brakes is required by regulation to be indicated by either acoustic of optical devices or a means of visually checking the degree of brake lining wear [1]. Current application of the wear indicator in the market uses either sound generating metal strip or wire harness based pad wear sensor. The former is not effective in generating clear alarm to the driver, and the latter is not cost effective, and there is a need for more effective and low cost solution. In this paper, a pad wear monitoring system using MOC(Motor On Caliper) EPB(Electric Parking Brake) ECU is proposed. An MOC EPB is equipped with a motor, geartrain and an ECU. The motor current when applying the parking brake is influenced by the mechanical load at the brake pad side of the system.

This paper presents semi-automatic parking assist system, which performs stereo vision based recognition of free parking site and parking guidance with automated steering operation. Pixel structure classification and feature based stereo matching extracts the 3D information of parking site. Parking site marking is separated by plane surface constraint and is transformed into bird's eye view, on which template matching is performed to determine the location of parking site. Obstacle depth map, which is generated from the disparity of adjacent vehicle can be used as the guideline of template matching by limiting the search range and the orientation. Proposed method using both the obstacle depth map and the bird's eye view of parking site marking increases the operation speed and the robustness to visual noise by effectively limiting the search range. Using this map information, geometrical relation is tested and efficient parking path is generated.

This paper describes the MANDO MGH ESP (Electronic Stability Program) and consists of the control philosophy, hydraulic actuator and the simulation and test results. The ESP system controls the dynamic vehicle motion in the emergency situation such as the final oversteer and understeer and allows the vehicle to follow the course as desired by the driver. The MANDO MGH ESP is integrated with the existing MANDO MGH ABS/TCS, which is improved with the more information and controls both brake pressure and engine torque for the optimal performance. The look-up tables are emphasized to have the accurate target yaw rate of the vehicle and obtained from vehicle test for the whole operation range of the steering wheel angle and vehicle speed. The wheel slip control is applied for the yaw compensation and the target wheel slip is determined by error between the target yaw rate and actual yaw rate.

This paper describes the development of Mando's new continuously controlled semi-active suspension system. The goals for the new system are 1) enhanced control performance and functionality for customer satisfaction and added value, 2) optimal design of variable valve for compact size, light weight and fast response. Based on the system requirements established from benchmarking and market needs, design of variable dampers, an ECU, sensors and control algorithms is carried out. Skyhook control is applied with a better road detection algorithm by using vertical wheel G sensors. New “Comfort” mode biased toward smooth ride adds more value to the vehicle. Co-operation with ESP helps increase the vehicle stability. Well-defined design procedure and test methods for verification and validation are followed. Simulation study, rig and vehicle integration test prove that the design goals are met.