Table of Content

25 January 2014, Volume 25 Issue 2

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Vibration Characteristics of a Double-direction TiNi SMA Ring Damper

Xiong Jiulang, Liu Jing, Xu Renbo

2014, 25(2):  143-146. 

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Using two groups of austenitic TiNi alloy rings as the energy dissipation components, a new type of damper was designed, and its structure and work principle  were introduced. The effects of the number of rings, longitudinal pre-deformation and the load on its vibration characteristics were measured by the vibration system. The results indicate that the vibration characteristics of the double-direction ring damper are complicated and different from that of the SDOF(single degree of freedom) system.At low frequency range (0~10Hz), the transmissibility is almost less than 1, that is to say, the vibration system is under vibration isolation area. The results show that the damper possesses a high damping capacity. Moreover its damping capacity can be improved by increasing the number of rings and longitudinal pre-deformation.

Vibration Control of Piezoelectric Flexible Structure Based on μ Synthesis

Hu Junfeng, Zhang Xianmin

2014, 25(2):  147-151,156. 

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Active vibration control of a smart flexible cantilever beam was studied by using mode theory and μ synthesis method. The actuator was piezoceramic patch, the sensor was strain gauge. The finite element method and experimental modal test were applied to obtain the dynamic model of the structure. Meanwhile, the results of comparative analysis of the two methods show there are errors between the finite element model and the actural system. Taking account into uncertainty of the external disturbance and measurement noises, and uncertainty of natural frequency, damping ratio and actuator parameters of the system, a μ synthesis approach was applied to design the vibration controller by selecting mode displacement as evaluation signal and selecting appropriate weighting function according to amplitude and frequency characteristics of the actual signals. First, the effectiveness of the controller was analyzed from a frequency domain point of view. The results show the controller can inhibit the impact of the uncertain disturbances on output strain, and can meet the control requirements in the case of uncertainty. Thus, the controller is robust. Second, the experiments on vibration control were performed. The experimental results show that the proposed controller can suppress the vibration response of the structure effectively.

Evaluation of Complex Surface Profile Errors Based on Subdivision and Sphere Approximation Method and Differential Evolution Algorithm

He Gaiyun, Liu Xin, Liu Peipei, Guo Longzhen

2014, 25(2):  152-156. 

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In order to evaluate the profile errors of complex surface,a subdivision and sphere approximation method, fast and convenient, was firstly presented. Approximating the surface patch containing the perpendicular foot of measuring point by a sphere, the shortest distance between a measuring point and surface was obtained. Secondly, a differential evolution algorithm was selected to optimize the position of measuring points. Finally, the evaluation of complex surface profile errors was realized by using subdivision and sphere approximation method combined with differential evolution algorithm. The proposed method was used to evaluate worm tooth-surface profile errors and the simulation results show that the method can obtain higher calculation accuracy compared with least square method and can satisfy the requirements of high-precision error evaluation.


Dynamics Model and Natural Characteristics of Cycloid Ball Planetary Transmission

Zhang Peng, An Zijun

2014, 25(2):  157-162. 

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Firstly, according to the loads distribution and variation, a translational-torsional coupling dynamics model of a cycloid ball planetary transmission system was established. Secondly, by analyzing the relative displacement relationships of each component, the dynamics equations of system were derived. And then, the natural frequencies and principal modes of the derivative system were present by solving the associated eigenvalue problem. Finally, the main structure parameters were selected to analyze the influences on the natural frequencies.


An Active Multiple Frequency Vibration Control Scheme of Grinding Wheel in Permanent Magnet(PM) Electric Spindle Rotor System

Qiao Xiaoli, Zhu Changsheng

2014, 25(2):  162-168. 

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To control vibration effectively, which had multiple frequency, caused by mass unbalance of grinding wheel and disturbance signals, this paper proposed a new active control strategy for suppressing the multiple frequency vibration of the grinding wheel in electric spindle rotor system, which was based on the LMS algorithm adaptive filter. The control scheme originated from the control principle of a bearingless PM motor. First, the winding configuration and principle of the PM two winding electric spindle and radial control force model were investigated.The dual winding PM electric spindle flexural rotor dynamics model was established by finite element and a FBLMS adaptive filter control algorithm was investigated. The multiple frequency vibration control effect of the grinding wheel, eddy loss of PM and stator core loss were investigated. The results show that the control scheme has an obvious control effect on suppressing the multiple frequency vibration of grinding wheel in electric spindle rotor system.

Multi-objective Optimization of Cutting Parameters during Milling of Titanium Alloys

Chen Jianling, Sun Jie, Li Jianfeng

2014, 25(2):  169-173. 

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A multi-objective optimization model of cutting parameters was built to solve the problem of high cost and low efficiency while milling titanium alloys. The maximized productivity and the minimized rate of tool life elapsed were selected as the optimization objectives. An extended non-dominated sorting genetic algorithm-Ⅱ(ENSGA-Ⅱ) was presented. A normalized process was added into the subroutine of initialization to get better variety and more uniformly distribution of population. In order to handle the multi-objective and multi-constraint more adaptively and effectively, a concept of non-dominance was defined extensively from the objectives space to constraints space based on the principle of Pareto optimality. A case was used to investigate the effect of the proposed approach. The results show that the approach gives a good performance in finding satisfying Pareto solutions. By means of this approach, the technician is able to flexibly select the cutting parameters according to the optimization objectives, and to better coordinate the relations between productivity, cost and surface quality.

Experimental Study on NC Grinding Surface Metallographic Organization of Spiral Bevel Gears

Ming Xingzu, Li Fei, Zhang Ran, Zhou Jing

2014, 25(2):  174-179. 

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Firstly, this paper used metallographic microscope to observe the surface microstructure characteristics of spiral bevel gears.The results show  that metallographic organization of gear grinding surface is acicular martensite+carbide+ residual austenite, carburizing layer metallurgical group is high carbon martensite+carbide+residual austenite, the heart of the department of organization is plate strip low carbon martensite+ferrite+bainite. Then the influences of different processing parameters on the spiral bevel gear surface metallurgical structure were analyzed through the orthogonal test method.Lastly,the optimal processing parameters were got through the range analysis. The results show that when the spiral bevel gear small wheel concave grinding process parameters for the depth of grinding ap=20μm, wheel speed vs=35.2m/s, workpiece speed vw=0.073m/s, namely austenitic residual volume is 15.6%, the level of acicular martensite is level 2, the organization optimal is optimal, so as to improve the influence law of gear fatigue performance and improve the wear resistance. A return content mathematical model of of the retained austenite in spiral bevel gear was established, the calculated value and maximum absolute value relative error of experimental measurements is 14.3%, showing that the regression mathematical model is relatively effective, and content of the retained austenite and experimental range analyses results are basically identical.

Distribution of Position and Orientation Errors for a 6-UPS Parallel Machine Tool

Chen Xiaogang, Sun Yu, Wu Haibing, Liu Yuanwei

2014, 25(2):  179-185. 

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A forward kinematics analysis for Stewart mechanism was extremely difficult, so the error analysis can not be carried out easily because it depended on forward kinematics solutions. To estimate the manufacturing accuracy of 6-UPS parallel machine tool BJ-04-02(A), which adopted a cross-link variation of Stewart mechanism as feeding mechanism, the principle of reverse thinking was adopted, thus the accuracy can be reflected by the change of link length for given pose(position and orientation) errors of cutter-platform. For each position point and orientation in workspace, the length changes of six actuating links were calculated for given pose errors of cutter-platform. Then the pose error limits of cutter-platform caused by link length unit error were obtained by extremum and reciprocal calculation. Finally the distributions of pose errors in workspace were provided.

Rolling Bearing Vibration Signal Fault Feature Extraction Based on Autocorrelation Analysis and LMD

Wang Jianguo, Wu Linfeng, Qin Xuhua

2014, 25(2):  186-191. 

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Rolling bearing fault vibration signals were nonstationary and multi-component modulated signals, especially in the early stages of the fault, fault features were difficult to identify because early fault signals were weak due to the weak modulation source and contained strong noise.The autocorrelation analysis and LMD method was proposed herein, it can extract fault features effectively. First, the noises were eliminated by using autocorrelation analysis, the periodic components in the signals were extracted. Second, multi-component modulation signals were decomposed into a number of product functions(PFs). Last, applying demodulated resonance technique to each  PF component, the fault feature frequency was extracted through envelopment analysis. The experimental results demonstrate the effectiveness of the method.

Current Control Algorithm of Permanent Magnet Synchronous Spindle Based on Tracking-differentiator

Yu Jiabin, Wang Xiaoyi, Xu Jiping, Qin Xiaofei

2014, 25(2):  191-196. 

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The conflict between overshoot and response speed inherent in current PI regulator of PMSS was difficult to resolve, which would lead to the overshoot in the current tracking process and increase the difficulty on tuning PI parameters. As the contradiction between “fast” and “overshoot” was the inherent property of PI regulator, based on auto-disturbances rejection control(ADRC) theory, tracking-differentiator was adopted to arrange transient process for d/q current commands and the tracking process of PI regulator for current step signal was smoother. Simulation and experimental results show that, compared with integral separated PI regulator, the current values can track the commands more quickly and smoothly, and the overshoot in transient process is eliminated and the system robustness is strengthened. 

Research on Coding System Based on Coding Segment Elements Reconfigurable Method

Xiao Xinhua, Wang Taiyong, Cheng Bing, Li Yu

2014, 25(2):  196-201. 

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In order to customize complex coding rules and to share coding segments, a concept of CSE was put forward. The subdivision method and types of CSE were presented. After studying the coding rule definition method based on CSE recomposing, the coding system functions were described. The key techniques such as CSE realization method, database design and PDM integration model were researched. Cases show that the method can support complex coding rules definition and reuse CSE data, therefore the cost of development and maintenance of coding system is reduced.

Review on Fund Management of Mechanical Engineering Discipline of NSFC in 2013

Wang Guobiao, Lai Yinan, Song Jianli

2014, 25(2):  202-210. 

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The applications, evaluations and funding of science funding projects in division of mechanical engineering of NSFC in 2013 were reviewed. Applications,evaluations and funding conditions were analyzed, taking projects in the fields of mechanical bionics and component machining and manufacturing as examples. Research progresses of finished and understudied projects in 2012 were summarized, and problems and items should be noticed were also proposed. Typical achievements obtained under the funding of science funding projects in the fields of mechanical engineering in 2013 were reviewed and management measurements on promoting academic exchange and cooperation, cultivating of young talents and encouraging innovation were presented. Main work plan and prospects in 2014 were also proposed.
 

A Study of Influence of Grinding Parameters on Surface Characteristics during Grinding GH4169 Superalloy

Huang Xinchun, Zhang Dinghua, Yao Changfeng, Ren Jingxin

2014, 25(2):  210-214. 

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The cylindrical grinding experiments by using different characteristics for the grinding wheel of the GH4169 superalloy were studied by the single factor experimental method. The influence of the single crystal corundum wheels and CBN wheels on surface roughness and surface topography in the grinding surface characteristics of GH4169 superalloy were researched, the influence regularity of grinding parameters on the surface roughness and chip shape was analysed, and the grinding surface topography was observed. The results show that, when cylindrical grinding GH4169 superalloy by using the single crystal corundum wheels, with particle size for 80, ZR1, the binders for ceramic, the surface characteristics is more stable, and the surface roughness is lower, the trajectory of grinding feed movement constitutes the main feature of the machined surface topography. However, with the workpiece speed ranging from 8m/min to 21.66m/min, the wheel speed from 15m/s to 30m/s, the radial feeds from 0.005mm to 0.02mm, the longitudinal feed from1.3~3.6mm/r to 3.6mm/r, the surface roughness can be controlled within the value of 0.14μm.

Identification of Engine Inertia Parameters Based on Frequency Response Function Screening

Long Jiangqi, Xu Chuanyan, Gao Jianxun, Zhou Sijia

2014, 25(2):  215-217,235. 

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The engine inertia parameters are defined by the mass, the center of gravity, the principle inertia of moments and their associated principle axes. On the basis of FRFs derived from vibration model test, a residual inertia method that allowed the simultaneous estimation of all the ten engine inertia parameters was presented. The method can identify all the ten inertial parameters of the engine accurately. According to a certain error limit level, appropriate FRFs of good reciprocity were selected to improve recognition accuracy. The validity of the presented analysis was confirmed by bench test results.

Research on Input/Output Characteristics of a Six-axis Piezoelectric Accelerometer

Chen Peng, Li Chenggang, You Jingjing, Hou Shijie

2014, 25(2):  218-222. 

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Six-axis accelerometers based on parallel mechanisms generally have complex decoupling processes and low efficiency. In view of this situation, a model of an existing six-axis piezoelectric accelerometer was bulit in ADAMS and the model was used to study the characteristics of the output in different inputs, to study the effects of the motion of the moving platform relative to the static platform on the calculation efficiency and computational accuracy and to plot some curves to show the relationship among the errors and the linear amplitude, linear frequency, angular amplitude and angular frequency of the input of the acceleration. Based on the research, an additional error will be brought in if the motion of the moving platform relative to the static platform was ignored during the decoupling process and the error mainly depended on the input of the acceleration. As long as the input of the acceleration satisfied the given requirements, the simplified decoupling processes can be used to solve the acceleration,and the additional error will be less than 0.2% while the calculation velocity will improve about 2 times.

Experimental Research on Ring Wire WECM with Wire Travelling in One Direction

Zhang Hai, Zeng Yongbin, Yu Qia, Zhu Di

2014, 25(2):  223-225. 

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The electrolysis products in the gap always affected the WECM precision, a ring wire travelling in one direction during the process was proposed to enhance the efficiency of removing products, and the wire tension was controlled in constant to ensure the stability of wire travelling. The influence of several processing factors, such as wire travel speed, feed speed, concentration of electrolyte and voltage, on the machining process was investigated. Structures with high-aspect-ratio were fabricated, the width of the slits was 250μm and the aspect ratio of the slits was nearly 20.

Die Service Life Estimation Based on Modified Archard Method in Forging Spiral Bevel Gear

Gao Zhenshan, Deng Xiaozhong, Chen Fuxiao, Li Tianxing

2014, 25(2):  226-229. 

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The die wear was simulated by elasto-plastic finite element model herein. Based on the modified Archard method, the die wear was analyzed from four processing factors, which were the addendum transition arc of tooth die, the die hardness, initial die temperatures and the forming velocity. Through the simulation results, die service life influenced by the processing factors was revealed. The optimal processing factor combination guiding the experiment was proposed by orthogonal experimental design. The experimental results indicate that there is expected consistency between the die service life and the experimental conclusion by using the method preceded herein.

Study on Vibration Attenuation in Jumping Frequency Interval of Quasi-zero Stiffness Vibration Isolator

Xu Daolin, Yu Qiping, Zhou Jiaxi, Zhang Jing

2014, 25(2):  230-235. 

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The performance of QZS isolation system was uncertain in the jumping frequency domain. To solve this problem, this paper proposed a damping perturbation control method. When the system damping was increased to a certain extent, the jump-down frequency will be lower than the excitation frequency. The large amplitude vibration response on the resonance branch will become unstable and drop to the non-resonance branch with small oscillation. The von der Pol plane was used to determine the timing of withdrawnness of the control to ensure that the vibration state ultimately rested on the non-resonance branch. The method makes attenuation available in the jumping frequency domain and broadens the frequency range of effective isolation of QZS vibration isolation system.

Dynamics Characteristics Analysis of Anti-rotation Mechanism of Mini-crank in Scroll Compressor

Li Chao, Zheng Shangshu, Zhao Man, Yu Yang

2014, 25(2):  236-241. 

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To study the dynamics characteristics of oil-free scroll compressor anti-rotation mechanism, a model of anti-rotation mechanism of mini-crank was established. On the basis of operation principle of anti-rotation mechanism of mini-crank, the force action on the mini-crank was analyzed with the kinematics and the mechanism, and the motion equation of mini-crank was established. Three-dimensional model of a mini-crank was established by 3D modeling software and finite element analysis software ANSYS. The number of anti-rotation mechanism of mini-crank has three, the deformation and stress state of the mini-crank in the different crank angles were analyzed, fatigue strength under alternating loads of the mini-crank was studied and the compatible state of deformation between three mini-cranks was discussed. The results show that the maximum deformation occurs in the upper and lower ends and the maximum stress occurs in the upper and lower ends and intermediate undercuts part in mini-crank.

Analysis of a 2T1R Fully Decoupled Parallel Robot Mechanism and Its Characteristics

Dou Yuchao, Zeng Daxing, Li Mingyang, Hu Xinzhe, Hou Yulei, Zhao Yongsheng

2014, 25(2):  241-245. 

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This paper presented a fully decoupled parallel mechanism with one degree-of-freedom(DOF) translation and 2-DOFs rotation. The motion feature of the mechanism and its number of DOF were analyzed by the constraint screw method. The analytical expression of the forward and inverse position for the mechanism was derived, and the expression of the Jacobian matrix was deduced, which validated the decoupling feature of the mechanism. The singularity of the mechanism was also carried out. The novel decoupled parallel mechanism presented herein enriches the mechanism structure, and the performance analysis confirms the decoupling characteristics of the parallel mechanism and establishes the theoretical foundation for its further applications.

Reliability-based Robust Optimization Design Based on Strategy of Multi-objective Optimization Uncoupling or Decoupling

Zhang Ruijun, Qiu Jiwei, Wang Xiaowei, Dong Mingxiao,

2014, 25(2):  246-250,272. 

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Targeting at realizing reliability-based robust optimization design of a multi-objective optimization, the additional items of sensitivity were generated via analysing of objective functions and constraints. And a model of reliability robust-optimization design was proposed based on the additional items of sensitivity. The impact degree of design variables on design objectives was determined by using the orthogonal experiment and variance analysis that were based on the axiomatic design. Design parameters were classified into groups by the uncoupled or decoupled optimization design that can make the optimization problems of multiple objective into single objective and can avoid the trade-off between design objectives. With the augmented multiplier method,reliability-based robust optimization design of caliper disc braker can be proceeded by using the software of symbolic toolbox and optimization toolbox of MATLAB. The numerical example shows that the proposed approach has higher precision and reliability.

Research on Deforming Force of Slab Cold Roll-beating

Yuan Qilong, Li Yan, Yang Mingshun, Li Yuxi

2014, 25(2):  251-256. 

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Firstly, the principle of slab cold roll-beating was simply described herein. Finite element model of slab cold roll-beating was established with ABAQUS and the simulation was completed. According to the simulation results, the changes of deforming force and the influences of processing parameter changes on the deforming force were analyzed. In combination with cold roll-beating experiment, the comparative analysis between the simulation results and the experimental ones was completed, which tested the validity of the finite element model.

Theoretical Analysis of JCO Forming and Springback for Sheet Metal Four-point Bending in Manufacture of LSAW Pipes

Sun Honglei, Song Xiaokang, Ma Rui, Zhao Jun

2014, 25(2):  257-262. 

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This paper presented a new technology for forming LSAW pipes called by “four-point bending JCO process”. In the manufacture of LSAW pipes through this new technology, the end surface is a circle of equal curvature. Other advantages of the new technology include fewer steps in formation and higher productivity. The theoretical analysis was verified by the experimental results. These will provide a theoretical basis to control the forming curvature by adjusting the punch displacement during each stage of bending in real manufacturing. Both the theoretical and the experimental results show the linear relation between bending and forming curvatures, thus provide a convenient means to intelligent control over the four-point bending JCO forming process. Based on the above theory and with the help of the new technology, the ideal LSAW  forming pipe is obtained in only 13 steps. Since the traditional process entails 25 steps, productivity is significantly increased.

Experimental Study on Deformation Law of Multi-stage Single Point Incremental Forming

Jin Lingling, Gao Lin, Shi Xiaofan, Zhang Qilong, Xu Jiahui

2014, 25(2):  262-266. 

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Flowage property and strain distribution was studied based on the deformation trend of the part gained by multi-stage single point incremental forming. Experimental results show that exists a significant second major strain, increasing with increase in forming depth and wall thickness decreases with increase in forming depth for the part gained by multi-stage forming. Increasing the quantity of stage can improve the forming quality. Further more, according to the analyses of the experiments, a limitation in forming depth in multi-stage single point incremental forming was proposed.

Analysis of Damage Behavior of Heavy-haul Railway Rails

Guo Huoming, Wang Wenjian, Liu Tengfei, Liu Jihua, Guo Jun, Liu Qiyue

2014, 25(2):  267-272. 

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The damage behavior and mechanism of heavy-haul rails were investigated in detail using various examinations by means of inductively coupled plasma spectrometer, hardness tester,optical microscope and scanning electron microscope. The results indicate that high content of carbon, silicon and manganese elements result in excellent strength, hardness and wear-resistance of heavy-haul rails. The surface hardness of damaged rail in the field is higher than that of new rail. Furthermore, the hardness of rail corner and head zone is higher than that of no-wear regions. The residual stresses of damage and new rails presented compressive stress state. Fatigue cracks always initiated from the rail head surface and then the propagation of cracks appears different crack angles. The intergranular and transgranular growth are dominating propagation modes for the heavy-haul rail cracks. There is almost no fatigue crack on side wear area. In addition, there is severe plastic deformation on the rail head zone and the microstructure is crushed and exhibits obvious streamline. The thickness of deformation layer is roughly the same with crack's growth depth.

Continuous Curvature Trajectory Planning Method of Large Angle Steering for Intelligent Vehicle

Li Aijuan, Li Shunming, Shen Huan, Zhao Wanzhong

2014, 25(2):  273-278. 

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In order to make the intelligent vehicle can run on the large angle curve road smoothly, a new curvature-continuous obstacle avoidance trajectory planning method was introduced. The trajectory planning method was based on β-spline and utilized the convex property of β-spline. The effection of several nonholonomic constrained conditions to trajectory planning was considered in this method. The nonholonomic constraints included obstacle avoidance constraint, curvature constraint, rotational speed constraint, speed constraint, state constraint and so on. An intelligent vehicle's right-angle curve road running trajectory was generated. The trajectory was obstacle avoidance and the curvature was continuous. The intelligent vehicle's right-angle curve road running experiments were done to test the trajectory planning method. The results show that this method is more effective and feasible than the traditional method. Using this method curvature-continuous trajectory can be generated and making the vehicle run along the trajectory smoothly.

Nonlinear Estimation of Vehicle Sideslip Angle Based on RLS

Xie Shaobo, Wei Lang

2014, 25(2):  278-283. 

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A model-based estimator of sideslip angle was proposed, and a time-varying parameter was introduced in Magic Formula tire model to be adapted to the roads with different friction coefficients. State space RLS was used and a nonlinear vehicle model was established to design the estimator. The slalom test on the high friction road and three double lance change tests on different friction roads were conducted to evaluate the estimator, and the results show that this method can estimate the sideslip angle accurately even when the vehicle has the large sideslip and the tire takes on the severe nonlinearity. Finally, the RLS is compared with the extended Kalman filter in the terms of the accuracy, computational efficiency and utility condition then to further indicate the performance of the estimator.