Gong Haibin

An Image Enhancement Method Based on Gamma Correction

The research of the wheel alignment system based on computer vision is a popular field for automobile safety. For realizing the effective and accurate feature recognition for the chessboard calibration target of the system, the enhancement algorithms based on Gamma correction are indicated. According to the research object, identification requires decreasing the pixel values in low grayscale and increasing the pixel values in high grayscale while keeping the pixels values in the middle grayscale. For this purpose, the novel Gamma correction curve is presented to enhance the target image. Experimental result shows that the enhancement method increases the contrast ratio of the chessboard target image which is benefit for feature extraction, points matching and vision measurement. Its effect and reliability meet the requirements of the detecting system for vehicle wheel alignment based on computer vision.

A Feature Points Matching Method for Calibration Target Images

Feature matching is a crucial research in computer vision. For realizing the effective and accurate feature matching for the feature points in the images of chessboard calibration target used in the wheel alignment system, the popular calculation algorithms are analyzed. The traditional polar constraint and polar equation for solving the problem constructing the relationship between corresponding points are indicated. A novel process which is special for matching calibration target images including sequential consistency constraint, polar constraint, distance constraint, uniqueness constraint are presented. Experimental results show that the matching precision and reliability of the method meet the requirements of the vision detection system for vehicle wheel alignment.

A Novel Corner Point Detector for Calibration Target Images Based on Grayscale Symmetry

The research of feature corner recognition for the calibration target is a crucial area for a vision-based measurement system. For the disability of detecting the corner’s location in a vehicle test system accurately, the theoretical errors based on Harris algorithm are analyzed. Experimental results show that the method can not be used in the vision-measured field as the corner cluster phenomenon. The novel corner detection algorithm based on grayscale symmetry is presented. The Gassian weighted symmetry detector is designed to illustrate the symmetrical feature around the optimal corner. Further Experimental results show that the detector proposed can be used to test the corner locations of the calibration target precisely.

Research on Automobile Suspension Performance Evaluation System with Adjusting-Frequency Method

Suspension is a crucial assembly for automobile controlling stability and safety. For achieving the effective and precise detection the suspension system, the simulation model based on 1/4 vehicle dynamic model is constructed. The model includes linear sinusoidal frequency excitation signal, 1/4 vehicle suspension’s two degree of freedom vibration system, body acceleration, relative dynamic load, the output model of suspension’s dynamic deflection. Simulation results show that in the condition of linear sinusoidal frequency excitation, the amplitude-frequency curves of vibration response values such as the vehicle body’s acceleration, the wheel’s relative dynamic load and suspension’s dynamic deflection which obtained by simulation accords with the law of 1/4 vehicle suspension’s vibration model and theoretical analysis. Vibration response value causes resonance phenomenon and generates peak values in the vicinity of 1 Hz and 11 Hz. From amplitude-frequency curve, we can determine frequency components and frequency distribution range of vibration signals, define the amplitude and energy of every frequency components, and accordingly carry out fault diagnosis on the vehicle’s suspension system.

Design and finite element analysis of shaking table for fatigue test of high speed train transmission system

With large scale increases of the train speed, it is of great practical significance to develop a fatigue test stand for high-speed trains transmission system. 3-DOF (three degree-of-freedom) electro-hydraulic shaking table for high-speed trains transmission system fatigue test is designed and its three dimensional mathematical model is established in this paper. In addition, static analysis and modal analysis of this shaking table are carried out by finite element analysis software. The results show the rationality of our mechanism design. The above research work lays the foundation for structural improvement and optimum design of shaking table.

The verification of the feature model accuracy for semi-trailor vehicle braking performence testing based on adams

Semi-trailers deflexion-angle is one of the important contents in the detection of wheel alignment parameters. The research of deflexion-angle detection is a crucial area for automobile safety. For the disability of measuring semi-trailers deflexion-angle, the UA tire-ground model is established. By the simulation of this model, the influence of semi-trailers deflexion-angle on semi-trailer trains braking performance is analyzed, quantitatively. The experimental results show that braking distances errors of the model in three times are 3.92%, −2.89%, −1.43%, respectively. The simulation braking folding angle and braking deceleration curves are also in accord with real vehicle experimental results. The established semi-trailer trains model is basically consistent with the real vehicle in braking condition and can be adopted to determinate the reasonable value of semi-trailers deflexion-angle and deflexion-angle detection.

Research on Calibration Theories and Experiments of Vehicle Wheelbase Difference

Considering the disability of calibration theories and methods for the tester of automobile wheelbase difference, mechanical analysis of the vehicle stability is employed to dedicate the negative influences of wheelbase difference. A novel device can realize calibration of the wheelbase difference within the range of 0-40 mm by variable wheelbase mechanism is proposed. Two diagnosis systems which suit the situations that the vehicle is driven in a straight line or a curve are presented. Calibration results of the tester show that maximal detection error of the measured points reaches 0.57 mm which is more than ±0.2 mm in the calibration standard. Experiments prove that the calibration methods proposed can verify the results of wheelbase difference tester fast and accurately.

Experiments on the Stability Steering Performance of Semi-Trailer Model

Deflexion-angle is a crucial parameter for automobile controlling stability and safety. For constructing the basement of deflexion-angle detection, the model of semi-trailer train’s suspension is built and leaf spring dependent suspension is replaced with helical spring dependent suspension in the model. Balance suspension is adopted to distribute axle load uniformly. The mainly measuring parameters of stable steering performance including tractor speed, tractor’s lateral acceleration and semi-trailer train’s folding angle are also tested in the experiment. Comparison of experiment and simulation results show that there is consistency between the stable steering performance of established semi-trailer train’s model and real vehicle, and we can perform reliable analysis and research by the established semi-trailer train’s model.

Simulation and Experiment on the Semi-Trailer Stability Steering Performance Caused by Deflexion-Angle

Deflexion-angle is a crucial parameter for automobile controlling stability and safety. For constructing the basement of deflexion-angle detection, the model of semi-trailer train’s suspension is built and leaf spring dependent suspension is replaced with helical spring dependent suspension in the model. Balance suspension is adopted to distribute axle load uniformly. The mainly measuring parameters of stable steering performance including tractor speed, tractor’s lateral acceleration and semi-trailer train’s folding angle are also tested in the experiment. Comparison of experiment and simulation results show that there is consistency between the stable steering performance of established semi-trailer train’s model and real vehicle, and we can perform reliable analysis and research by the established semi-trailer train’s model.