Electronic Power Steering System Research Articles

Model-based safety assessment with SysML and component fault trees: application and lessons learned

Mastering the complexity of safety assurance for modern, software-intensive systems is challenging in several domains, such as automotive, robotics, and avionics. Model-based safety analysis techniques show promising results to handle this challenge by automating the generation of required artifacts for an assurance case. In this work, we adapt prominent approaches and propose to augment of SysML models with component fault trees (CFTs) to support the fault tree analysis and the failure mode and effects analysis. While most existing approaches based on CFTs are only targeting the system topology, e. g., UML class diagrams, we propose an integration of CFTs with SysML internal block diagrams as well as SysML activity diagrams. We realized our approach in a prototypical tool. We conclude with best practices and lessons learned that emerged from our case studies with an electronic power steering system and a boost recuperation system.

Electronic power steering system – A mechatronic model for simulative analysis of power consumption

Dynamic modelling of electronic power steering (EPS) systems is an essential part of vehicle dynamics simulation during the development process in automotive industry. Most of existing models focus on mechanical or driving-comfort issues (i.e. steering ripple analysis) but do not consider precise modelling of the power consumption of the system. However, correct dimensioning of board net components requires accurate predictions of the system's power demand as early as possible. In order to fill this gap, this article presents both modelling and parameter identification of a steering system with a simple mechanical module and a detailed representation of the electrical subsystem. Accuracy of the developed modelling approach is validated against test bench and vehicle measurements.

Exploration of the Reliability of Automotive Electronic Power Steering System Using Device Junction Electrothermal Profile Cycle

This paper focuses on the driving steering load cycle stress-strain, shake, and transient temperature profiles in relation to failure in an automotive electric power steering (EPS) system. A compact EPS control system model was applied to construct a lookup table for the device power loss calculations. The lookup table was used to obtain the full electrothermal profile of a vehicle EPS system converter. An accurate thermal model was introduced using FLOTHERM software and compared with the results from EPS device temperature testing. The transient junction temperature profiles of the device were studied based on the operational cycles of the vehicle EPS system. Finally, an efficient rainflow cycle counting method was introduced to obtain the statistic random transient thermal stress cycles. Miner’s rule was also explored, and the relationship between the accumulated thermal stress damage and material fatigue was used to predict the converter’s reliability.

Research on Elastic Damping Control Strategy at High Speed for a Vehicle Electronic Power Steering System Stability

Electronic power steering (EPS) system is a critical component for vehicle safety driving. The damping force of automobile steering is decreased at high speeds, so the driving feel is floating. When vehicle suspension shock and a front wheel sensitive to road counterforce it is relation with the driver safety. For the subject of vehicle stability at high speed, an EPS system control strategy of stability has been presented. In order to keep driving feel, when the steering resistance decrease an elastic damping will be increased. Current follow control technique is introduced, and the torque sensor can estimate the vehicle state. This method can be verified by the experiment.

Annoyance evaluation of interior vehicle motor noise by impulse response method

In this study, the annoyance of EPS(Electronic Power Steering system) motor noise in a vehicle was evaluated through the anechoic chamber test. Evaluation during actual operation installed in vehicles allows in-situ annoyance tests, but requires a great deal of labor and time. Therefore anechoic chamber test is required to automate the evaluation process under consistent test condition. However vehicle noise test is significantly different from anechoic chamber test from different sound generation and propagation. Due to these discrepancies, the evaluated results among motors open differ between two test results. For consistent test results compared to those obtained from the actual vehicle environment, impulse response of both the vehicle interior and anechoic chamber was measured, and produced a simulated motor noise by using recorded signal in the anechoic chamber. The important peak noises at 1/3 octave bands to take into account of the tonal components were selected for evaluation of its noisiness. From the multiple regression model, the annoyance of motor noise in vehicle using the anechoic chamber test was evaluated.

Neural Network Control of EPS Based on the Cerebellum Model

A mathematical model of vehicle electronic power steering system (EPS)is established. To meet the response speed and real-time requirements of the EPS control, A neural network control strategy of EPS based on the cerebellar model is designed, steering system dynamic response is analyzed and EPS controller based on a single-chip computer with ARM kernel is developed, On the basis of the simulation road test of vehicle is carried out. The results show that the CMAC neural network control of EPS can well coordinate the contradiction between portability and flexibility, It can improve vehicle handling stability and the comprehensive performance of the vehicle.