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SS316TI steel

2013年9月4日 by admin

SS316TI steel

Steer-by-Wire system is an electronic control steering system with totally new concept which cancels the mechanical joint between the steering wheel and the front wheel; it makes vehicle steering following the driver’s command and generate a reaction torque to the steering wheel, as a virtual feedback of the road feeling by the steering motor and the steering feel motor respectively. Steering-by-Wire system makes the design of steering characteristics more freely and leaves a bigger space for improving the stability and the safety of the vehicle, which represents the future trend of the steering system of the future vehicle, especially intelligent vehicle. The fault tolerance control technology as an important part of control strategy of Steering-by-Wire system is one of major means for guaranteeing reliable operation of the whole system, so it is the indispensable primary factor of the control method for Steering-by-Wire system.This Ph.D. dissertation is based on the project named“Research on Key Technology for Front Wheel Steer-By-Wire Vehicle”(No. 50475009) and“ResSS316TI earch on Control methods and Key Technology for X-By-Wire Vehicle”(No. 50775096) by National Natural Science Foundation of China. Based on the summary of the domestic and foreign research achievements on fault-tolerance control technology for Steer-by-Wire automobile,this dissertation aimed at security and reliability of Steering-by-Wire system and made a deep study of fault tolerant control over main sensors, steering motor and controller. The control method is tested with Hardware-in-Loop simulation. On the basis of this, it is further confirmed by real vehicle test and the Steering-by-Wire automotive is modified from one domestic car. The main research work is summarized as follows:(1)Establish the fault tolerant control method for Steer-by-Wire system based on residualAim at the characteristics of Steer-by-Wire system and the necessity of on-line fault tolerant control, the fault tolerant control method over sensors, steering motor and controller, of Steer-by-Wire system, is studied in this paper. And one residual detecting fault tolerant control algorithm based on Three Voting Protocols is proposed from two sides, including fault diagnosis and fault compensation. It could get the residual matrix for sensor fault tolerance control by the combination of sensor measurement and estimated value, and the fault eigenvector by comparison among different residual, thus realize fault diagnosis. Toward the faulty sensor, fault compensation can be achieved by backup sensor and dual redundant of software eSS316TI stimated value, to make sensors reliable and stable; In fault tolerant control over motor, main parameters of the motor can be obtained by Parameter Identification. The parameter of the motor is estimated too with its working status, by parameter estimation method. And then, the fault tolerant control over motor can be achieved with the residual between estimated value and real parameter of the motor. The fault compensation of motor is mainly warning to driver; In controller fault tolerance, Tri-core structure is adopted and the fault diagnosis residual is built by dual redundant of haSS316TI steelrdware and arbitration of data inside the chip. The fault compensation of controller is accomplished by backup hardware. In a word, according to the characteristics of different components in Steer-by-Wire system and the residual detecting method, the fault tolerance control of sensor, motor and controller is realized.(2)Establish the method for sensor fault tolerant control based on Riccati equation and state estimation with Adaptive Kalman FilterConsidering the construction characteristic of Steer-by-Wire system, the entire system is divided into two parts: steering wheel module and steering actuator module.To the angle sensorSS316TI  in the steering wheel module, software signal estimation can be obtained by the method of faulty signal reconstruction which is based on Riccati equation. Residual matrix will be constructed with the dual-backup sensor. And then, according to Three Voting Protocols, the fault diagnosis can be realized with the given threshold and by using the backup sensor to bring about fault compensation. The sensor fault tolerance of steering actuator module is relatively more complex. Key sensors needing fault tolerance control include pinion shaft steering sensor, rack displacement sensor, yaw rate sensor, lateral acceleration sensor and motor current sensor. On the basis of whole vehicle model combined Steer-by-Wire system, the state estimation methods for Steer-by-Wire automobile is obtained with Adaptive Kalman Filter. And then, based on the above efforts, build residual matrix combining hardware signal and estimated value, and determine residual threshold according to dependencies between different signals and the tire mechanics character. The fault eigenvector will get then, so it realizes sensor fault diagnosis and fault compensation by backup hardware and software estimated value.(3)Establish the method for SS316TImotor fault tole steelant control steelbased on Adaptive Kalman FilterThe steering motor as a source of steering power, it plays an important role in Steer-by-Wire system. In this paper, based on motor model which have built and Adaptive Kalman Filter theory, the parameter estimator for the steering motor is built to estimate internal resistance and torque constant of the motor and the actual value of these two parameters are identified by using the Least Square Algorithm. And the residual can be calculated by the parameter value obtained with the two methods mentioned above. And then, motor fault diagnosis can be achieved with the threshold. After the fault information is acquiredSS316TI , it needs to make travel security by warning to driver.(4)Establish the method for controller fault tolerant control based on Tri-core controller and TTCAN busIn this paper, controller fault tolerant control for steel the Steer-by-Wire system can be implemented by Tri-core controller, and the fault tolerant control of signal conditioning circuit and driver circuit can be done by dual-backup hardware. Three cores consist of two main control chips and one arbitral chip. The arbitral chip shall be mainly responsible for making control decision for fault diagnosis and fault compensation of the signal conditioning circuit, main control chips and driver circuit. The residual can be calculated by hardware signals and the built-in reference values in the arbitral chip, and fault can be determ steelined according to the threshold. And then, fault compensation is realized by backup hardware. Due to the real-time requirement of controller fault tolerant control, the communication between main control chips and arbitral chip needs to meet the real-time requirement. In this paper, the communication among these chips is achieved through TTCAN bus based on event trigger mechanism, to achieve real-time transmission of fault tolerant information. Based on the rSS316TI esearch above, the fault tolerant controller for the Steer-by-Wire system can be made.(5)Design and build Hardware-in-Loop test rig and experimental car of Steer-by-Wire system and verify the fault tolerance method by the experiment in the test rig and experimental carBased on the study above, the rapid prototyping platform is built for the study on fault tolerance control with Matlab/xPC Target. And the Hardware-in-Loop test rig of Steer-by-Wire system is built too, combined hardware of Steer-by-Wire system, resistance simulator and small driving simulator. Under the research result stated above,the fault tolerance control method for sensors, motor and controller of Steer-by-Wire system is validated through Hardware-in-Loop simulation. Taking one domestic brand, class-A vehicle as the platform, the vehicle is modified into a Steer-by-Wire vehicle with our own Steer-by-Wire system. And the fault tolerance control method for sensors, motor and controller is further validated. The result has fully validated the efficiency and accuracy of the fault tolerance algorithm.So all in all, the innovative achievements made in this paper are shown as follow:(1)According to the characteristics of Steer-by-Wire system and the practical situation of fault tolerance control, the fault tolerant control method based on residual detecting is proposed. In accordance with different characteristics of different components including sensor, motor and controller, the residual matrixes for each component can be obtained by the combination of hardware signal and software estimated value. And combining it with the given threshold, make the fault tolerant control of components come true. (2)By applying Adaptive Kalman Filter theory to the fault tolerant control of sensor and motor of Steer-by-Wire system, and with the Steer-by-Wire vehicle model and motor model, the state estimator and the parametSS316TI er estimator are constructed, to provide reference signal for sensor and motor fault tolerant control and fault compensation signal for sensor. According to the actual situation of multi-sensors fault tolerant control, the concept of sensor fault eigenvector is given. Finally, the quick and accurate sensor fault tolerance is realized through a simple comparison of residual.(3)By applying TTCAN bus which is based on event trigger mechanism to the fault tolerance controller design of Steer-by-Wire system, and based on actual needs, the fault tolerant controller is designed by the Tri-core controller architecture which includes two main control chips and one arbitral chip

SS316TI