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Table of Content

    10 June 2016, Volume 27 Issue 11
    Bionic Hip Joints Based on Bias Output 3-RRR+(S-P) Spherical Parallel Mechanisms
    Yang Yajing, Sun Tongshuai, Zhou Yulin
    2016, 27(11):  1421-1428. 
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    Based on the 3-RRR+(S-P) spherical parallel hip joints with bias output, according to the bionic principles and referring to the structure of the femur, this paper determined the offset angle of the joint mechanisms, presented the coordination of the working spaces of the hip joints and the mechanisms, and ascertained the installing and locating angle of the joints on human body, which completed the design of the new humanoid robot hip joints. The paper made the mapping relationship between the spaces of the bionic joints and the mechanisms and solved the inverse/forward kinematics of the bionic joints.The numerical calculation shows that the joint mechanism may realize the basic movements of human hips, as well as the wireless wearable 3D inertia tracking equipment and magnetic movement tracking equipment from Xsens Technology Co. for the human natural gait. After mapping transforms and inverse solving,the information was imported into ADAMS for test. The results, which also verify the practicability and scientific values of the joints, support the mapping installing characterized angle and inverse/forward solutions proposed.
    Research on Mechanics Performance of a New Cambered Friction Damper
    Wang Gongxian, Wang Yangyang, Yuan Jianming, Yang Yi, Wang Dong
    2016, 27(11):  1429-1433. 
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    A new cambered friction damper was developed, which enabled to overcome the shortages such as poor adaptive capacity and low energy dissipation capacity. There was a block of rubber sandwiched between two sliders bent in a certain configuration. Frictional plates and the sliders were curved. The device dissipates energy through friction between the plate and slider. The mechanism model of the damper was established, and its rational was verified by numerical model. The influences of the initial compression of the rubber and the load frequency on the hysteresis damping characteristics of the damper were conducted. It is shown that the hysteretic curve of the damper is in map of pommel horse and the frictional force is varied with displacement. The energy dissipation capacity of the damper is stronger than that of the conventional one, which exceeds over 23.84%. The damper mechanics properties are less relevant with loading frequency, while the larger the rubber spring preload is, the stronger its energy dissipation energy capacity is.
    Design and Experiments of Recoil Mechanism Based on Fuze Micro-Electro-Mechanical System
    Deng Jufeng, Shi Chunjing, Hao Yongping, Xu Mahui
    2016, 27(11):  1434-1439. 
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    By using mechanics analysis and the work-energy theorem, the as value of the recoil was determined by elastic coefficient k,the gap d between two teeth in the vertical direction,the bevel edge a in the teeth,the bottom margin c in the teeth and the number n of teeth. The ADAMS simulation was used to determine the rationality of the motion equations and design, the relationship among elastic coefficient k,the gap d between two teeth in the vertical direction,the bevel edge a in the teeth,the bottom margin c in the teeth,the number n of teeth and the as value. The simulation results show that, under the same conditions, the machining errors of c are strictly controled. At the same time, the dislocation clearance of d is decreased and the line width of b is increased, to improve the recoil as values. The increase of n may be taken into consideration to improve the recoil as values. While the simulation experiments were carried out for the recoil mechanism, which was made by LIGA process, it verifies the rationality of the simulation analysis, and the machining errors have a great influences on the experiments. At the same time, it verifies the rationality of design and the motion equations.
    Study on Separating Displacement Models for Component from Waste Printed Circuit Board
    Xiang Dong, Wu Yujia, Yang Jiping, Long Danfeng, Mou Peng
    2016, 27(11):  1439-1445. 
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    Under conditions of melt solder, whether components might be disassembled was decided by the separating distance between components and the substrate (named as separating displacement) caused by removal force. Firstly, the models of separating displacement for surface mount devices (SMD) and through-hole devices (THD) were established under the conditions of vertical disassembly and horizontal disassembly. Secondly, based on the Laplace equation and the Newton’s equation for hydrostatic pressure, tensile breaking height of solder was analyzed and modeled in vertical disassembly for 3 typical kinds of components and the programmed algorithm was elaborated in detail. Finally, to verify the models for tensile breaking height of the melted solder, based on SMD with mounting base experiments were performed and the results show that the models for tensile breaking height are effective for melting solder. Models of separating displacements for components will be helpful to quantify the distance between components and the substrate, which is helpful for preparing the dismantling process of waste PCBs.
    Study on Precision Micro EDM of Torsion Bar Arc Grooves
    Huang Yuping
    2016, 27(11):  1446-1450. 
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    The influence of mechanical errors on machining precision were analyzed herein, the reasonable scheme of clamping was designed to reduce the influences of mechanical error on the manufacturing accuracy. Through the orthogonal experimental method, the influences of EDM parameters on the surface roughness of the arc grooves were analyzed, and the optimal parameters were obtained,Using the parameters, the arc groove surface of Ra=0.1μm can be obtained.Stiffness measurement device of torsion bar was developed,In the process of the torsion bar, the requirements of the surface shape precision and the machining rigidity are satisfied at the same time.
    Motion Characteristic Analysis of Screw-bushing Pair for Epicycloid Type Progressive Cavity Pumps
    Du Xiuhua, Liu Shuangxin, Tian Mi, Han Daoquan
    2016, 27(11):  1450-1454. 
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    A fixed contact point was found on the bushing bone line by analyzing the relative movement of epicycloid type progressive cavity pump screw-bushing pair, so the bushing might be made of metal and the metal screw surface might be made of rubber. The calculation formula of relative sliding velocity on convex tooth and concave tooth was derived by using the method of instantaneous center, then using MATLAB the velocity curve was built and using SolidWorks the solid model of PCP was set-up. Using SolidWorks Motion the simulation was carried on and then comparing the simulation values and calculation curves, they were in good fitting. The maximum deviation rate is only minus 0.101%. The maximum relative sliding velocity value of concave tooth is found in the middle of screw convex tooth contacting with the middle of bushing concave tooth, the maximum value of convex tooth is found in the middle of screw convex tooth contacting with the middle of bushing convex tooth.
    Research on Three-axis Linkage Shaping Technology for Non-circular Internal Gears
    Li Bo, He Jun, Zheng Fangyan, Chen Dingfang, Wu Junfeng, Lü Xiaobo, Wu Youan
    2016, 27(11):  1455-1460,1483. 
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    According to the normal vector of gear pitch curve, a linkage model of non-circular internal gear shaping was obtained based on the model of the envelope. And the conditions were given to avoid undercutting at the design of non-circular internal gear.At the same time, in the view of non-circular internal gear shaping process, the cutter retracting conditions and the methods of cutter retracting were given. Finally, the correctness of the model was verified by computer simulation and gear shaping processes.
    Research on Titanium Alloy Circular Hole ECM Based on Electric Field Analysis
    He Yafeng, Lu Wenzhuang, Gan Weiming,
    2016, 27(11):  1461-1466. 
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    Taking circular hole electric chemical machining(ECM) as an object, a theoretical model of circular hole was established by taking into account the mutual relationship of electric and moving mesh in process. The distributions of circular hole potential and current density, forming process and material changes were obtained by using numerical methods, the relationship among different processing parameters(the average voltage pulse, the electrical conductivity, the feed rate)and circular hole forming was discussed, And the circular hole ECM tests were done. According to the same processing parameters, circular hole theoretical depth 1.07mm is a better match circular hole experimental depth 1.157 14mm,thus it provides a theoretical basis for circular hole ECM.
    An Absolute Positioning Accuracy Analysis Method for Robot Based on Interval Analysis
    Huang Kang, He Chunsheng, Zhen Shengchao, Hong Jian, Zhao Fumin
    2016, 27(11):  1467-1473. 
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    This paper proposed a method for improving the absolute positioning accuracy of 6R robot based on the analysis of error sources. A more precise and closer extended forward kinematics was deduced based on modified interval calculation rules and POE formula. Then a hierarchy interval kinematics was proposed,which was easy to extended to other kind of robots as well as handle interval dependency,and the overestimation of which might be eliminated by interval matrix refinement developed herein. Monte Carlo samples and the results of contrast simulation between the hierarchy interval kinematics and existing extended interval kinematics show the presented kinematics can get as tight results as desired results more efficient than the existing ones. The presented method was executed on a 6R robot of an automatic transmission assembly line that plays role of tightening screws. Experimental results show that the proposed approach is more efficient and accurate than existing analytic methods.
    Design and Simulation Analysis of Compliant Mechanism with Two-DOF Based on Virtual Prototype
    Jiang Xianliang, Hong Huajie, Liu Hua, Li Zhiling
    2016, 27(11):  1473-1478. 
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    In order to meet the requirements of precise linear guide and a large travel distance, a two-DOF compliant mechanism was designed. The total design proposal was introduced and the characteristics of stiffness in the working direction was analyzed. For the further co-simulation in mechanical and electrical system, a virtual prototype model was established based on ADAMS and ANSYS to verify the designed stiffness and linear distance of the two-DOF compliant mechanism. The test results show that the stiffness in the working direction is much smaller than that in other directions, which meets the demands of precise guides. The linear distance is longer than 4mm, which meets the demands of distance of travel.
    Cutting Status Identification Method for Complex Parts Integrating with Process Informations
    Zhu Shaowei, Mou Wenping, Tang Limin, Du Li
    2016, 27(11):  1479-1483. 
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    In CNC machining of complex parts, the physical signal-based machining monitoring system was easily affected by the process fluctuations, which led to false alarms. In order to figure out this problem,two methods integrated process informations were proposed to improve the accuracy of cutting status identification. To test and verify their feasibility, a remote monitoring prototype system was developed based on the OPC interface of numerical control system, which identified the cutting status integrating with the process informations and real-time cutting power of spindle, and stoped the cutting once abnormal cutting was detected. Application tests were conducted on several typical aircraft structure parts, the results show that the accuracy of process identification is promoted after integrating with the process informations.
    Fault Diagnosis of Rolling Bearings Based on Generalized Morphological Filter and Hilbert Marginal Spectrum
    Cui Baozhen, Ma Zewei , Li Huilong, Wang Shan
    2016, 27(11):  1484-1488. 
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    Generalized morphological filter output could be good at eliminating the phenomenon of statistical bias, Hilbert marginal spectrum envelope method overcame the traditional needs to identify deficiencies bandpass filter center frequency and bandwidth. Combining the two methods mentioned, generalized morphological filter was used to complete the signal de-noising, then decomposing signals by EMD and then selecting the appropriate IMF components the partial Hilbert marginal spectrum of the signals was obtained. The bearing inner and outer ring fault diagnosis results show that the method may accurately extract fault features, which determines the type and location of bearing failure effectively, so it has wider applications in many fields.
    Fault Diagnosis of Permanent Magnets of Electric Car Hub Motor Based on Wavelet Analysis
    Pan Hanming, Lei Liangyu, Wang Zihui
    2016, 27(11):  1488-1492. 
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    This paper focused on the PMs fault diagnosis of outer-rotor-mounted elctric car BLDC motor, with the applications of wavelet analysis. Two types of fault were discussed, the uniformity of PM arrangement and the detection of PM demagnetization. The Hall sensor outputs of the hub motor were employed as the characteristic signals to diagnose the arrangement of PMs with the applications of wavelet decomposition method. Certain frequencies of the wave form of phase current were extracted and their energy percentages were computed, using continuous wavelet transform, whether a demagnetization fault occurred was judged during motor operations. Experimental results show that the informations of the non-uniformity and the demagnetization faults of PMs may be obtained by the methods mentioned above, which offer a new methodology based on wavelet analysis to diagnose the PM faults in the hub motor.
    Experimental Investigationon for Uniform-loading Adjustment among Different Pads of an Oil-film Thrust Bearing with GMA
    Wu Chao, Wang Wen
    2016, 27(11):  1493-1496. 
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    The structure and the principles of an oil-film thrust bearing were introduced based on GMA. The testing rig supported by this type of the bearings was built up. Running-in experiments, single-pad loading adjustment experiments and uniform-loading adjustment experiments including manual and automactic methods among different pads on the testing rig under different working conditions were completed to verify the performance of the thrust bearing. GMA was located at the supporting place of the pad and used to support the pad of the controllable bearing. Temperature signals as feedback parameters were used to control the magnetic field of GMA to alter oil-film clearance of the pad, which the load on a pad might be changed and was homogeneous to prevent the local high-temperature phenomenon of the bearing by controlling oil-film clearance at the supporting place of the pad. The results indicate that the controllable bearing with the GMA devices has the ability to adjust oil-film clearance of a pad and avoids imbalance load phenomenon among different pads and bears the uniform load for every pad for the same thrust bearing.
    Metal Micro Crack Detection Based on Vibro-acoustic Modulation Method
    Fang Piaopiao, Zheng Huifeng, Yu Sangsang, Zhu Keyi, Wang Yuebing, Cao Wenxu
    2016, 27(11):  1497-1501. 
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    In order to overcome the shortages that traditional linear ultrasonic testing could not detect the micro-cracks, VAM was studied. The VAM was simulated with finite element software ABAQUS to demonstrate the validity of the proposed method. The parameter setting of experimental testing system was also depended on the simulation results. VAM experimental testing system was established to investigate the nonlinear characteristic for micro cracks with variable lengths, and a quantitative characterization method was proposed based on information entropy of modulation signals. The results show that side-band signals are obvious when there is a micro crack in aluminum plate. The information entropy of modulation signals increases monotonically with increasing micro crack lengths and can be used as the characteristic parameter of crack length using VAM method.
    Synchronization Error Compensation Strategies in Dual-drive System for Servo Gain Mismatch
    Chen Lin, Cheng Zhengbo, Huang Bingqiong, Pan Haihong,
    2016, 27(11):  1502-1507. 
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    The mismatch of dual-axis servo gain parameters might bring negative impacts on the issues of synchronization in dual-drive system. To solve this problem, the relationship among tracking errors from single axis and the synchronization errors from dual-axis was investigated, by analysis of steady-state-error from single axis. Then the analytic formula of the synchronization errors was derived as reference position of ramp type applied. And then the quantitative relationship among the synchronization errors and parameters (the dual servo gain and feed rate) was built and determined.Furthermore, two novel compensation strategies for compensating synchronization errors were raised by introducing velocity factor into cross-coupling controller. Experimental and simulation results were given to verify the validity of the proposed scheme for obtaining synchronization errors. It can also be proved that both of two strategies can suppress synchronization errors effectively, which is caused by dual-axis servo gain mismatch. And the dynamic responses of single axis system is not affected after the proposed control strategies applied. By comparison of the two compensation strategies, smoother curve of synchronization errors may be obtained using the second compensation strategy.
    Regular Forging Energy Consumption Characteristics for Open-die Hydraulic Forging Press
    Yao Jing, Wei Chenguang, Li Bin, Wang Feixue
    2016, 27(11):  1508-1515. 
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    In order to analyze the energy distribution proportion of electro-hydraulic control system for a open-die forging hydraulic press, taking the regular forging process of 20 MN open-die forging press as the studied object and considering the operator influences, the operating mode and control method were given, the energy consumption calculation model and the hydraulic control system simulation model were established. Then, for the purpose obtaining the more accurate simulation model, the measured data of 20MN fast forging hydraulic machine was used to verify the simulation model. Furthermore, based on the simulation model, the energy distribution for 20MN open-die forging hydraulic electro-hydraulic proportional control system was simulated, especially focused on the influence rules of different loads and operator operating speed on the system energy consumption. The simulation results show that the energy utilization rate for 20MN open-die hydraulic forging press is only 14.3% under conditions of maximum load, the main reasons of low efficiency is the constant flow rate input can not match the varied velocities of the load, and the energy utilization rate proportionally improves with increases of the load and the operating speed. 
    Effects of Vane Wrap Angle on Flow Field and Non-overload Performance for Medium Specific Speed Pumps
    Ma Yi, Ma Zhongqiang, Zhang Shengchang, Wang Xinhua
    2016, 27(11):  1516-1522. 
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    To identify the effects of vane wrap angle for medium specific speed pumps, the centrifugal pump of D82-19-2 was chosen as the research subject. The design scheme of impeller and four impellers with vane wrap angle of 150°, 170°, 190° and 210° respectively were ascertained according to non-overload impeller constraint formula. The flow field and non-overload performance of the pumps were obtained by numerical simulations. By compared with experimental results, the deviations of simulated head, efficiency and power values are less than 9%, and the accuracy of simulation results was verified. The results show that with the increasing vane wrap angle from 150° to 210°, the inlet pressures of impeller increase by 24%, and low-velocity areas expand to one-third of the whole runner, that is, the fluid constraint ability and cavitation resistance have enhanced. However, the outlet pressures of impeller reduce and the kinetic energy losses aggravate for larger wrap angle. Meanwhile, the power reserve factor decreases from 1.145 to 1.025, and the extreme point of shaft power curve appears, so that non-overload characteristics of pump are more significant for larger wrap angle. But the pump head and efficiencies decrease by 15.4% and 4.48% respectively. The results may provide theoretical bases for non-overload design of medium specific speed centrifugal pumps.
    Differential Evolution Algorithm with Intergeneration Projection Operator
    Fu Chunming, Jiang Chao, Chen Guangsong, Ji Lei
    2016, 27(11):  1523-1529,1545. 
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    A DE based on intergeneration projection operator with good optimum and fast convergence performance was proposed to solve optimization problems. The proposed method based on the classical differential evolution mainly included the following characteristics. Firstly, for improving the diversity of population, opposition learning was employed to generate initial population and two different strategies were randomly selected to generate new mutant individuals. Secondly, an intergeneration projection operator was designed to generate three offsprings to substitute for the three worst individuals into the next generation. Thirdly, the exploratory operator was introduced to generate the new individuals into the next generation for keeping the diversity of evolutionary population and avoiding to obtain local solution. Finally, the performances of IPDE algorithm were verified by the eleven single-and multi-modal benchmark tests and two practical engineering problems.
    Power Shift Control Stratage for Heavy Mining Vehicles’ AT Based on Vehicle Load Coefficient
    Li Hao, Liu Jianxia,
    2016, 27(11):  1530-1534,1540. 
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    Automatic shift speed for heavy mining vehicles needed to meet different road condition demands at any time. A new shift control strategy was proposed in view of this situation based on the vehicle load coefficient, aiming at modifying the automatic shift strategy which commonly used speed and throttle opening as control parameters. A mathematical model of vehicle transmission system of a 32 tons mining tripper was built and the best shift speed point at different throttle openings and vehicle load coefficients was solved by graphic method. A simulation model of vehicle transmission system was established with MATLAB/Simulink and simulations were conducted. The results show that the revised shift strategy may adapt to a variety of working conditions and reduce the automatic gear patterns settings.
    Influence Mechanism of Residual Tensile Stress in SKD11 Steel Caused by Pulse Magnetic Field Treatment
    Luo Cheng, Li Zhenglong, Cao Hongzhi, Zhang Xianglin
    2016, 27(11):  1535-1540. 
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    Sevel single factor experiments were designed to explore the influence mechanism of residual tensile stress in the SKD11 steel by PMT.When the magnetic field strength, the magnetic field frequency, magnetic field direction and the processing time were varied individually,the changes of residual tensile stress in the sample were obtained.All experimental phenomena were explained from the angle of dislocation-nature of the stress. Process of PMT was divided into two stages in the explanation. The first stage was un-piling of the dislocation pile-up group and the second was multiplication of dislocation. Formula of Hp was deduced and Hp was the critical magnetic field strength which started the un-piling of dislocation pile-up group in the first stage. Formula of Hc and H'-pwere deduced. In the second stage,Hc was the critical magnetic field strength which started multiplication of a single Frank-Read dislocation source and H'-p was the critical magnetic field strength which made a single dislocation overcome the lattice resistance. The principals of PMT in the applications to stamping die were established based on the experiments and the theory.
    Basic Parameters in a New Bloom Crystallizer and Simulation on Its Inner Liquid Steel Behavior
    Zhou Chao, Ren Subo, Zhang Xingzhong, Liu Jingjing, Bai Minghua
    2016, 27(11):  1541-1545. 
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    In order to reduce the height of vertical continuous casting machine and diminish the equipment dimension, the casting speed and liquid core depth were calculated according to empirical formulas.Based on calculation and feasibility analysis,the appropriate casting speed is as 0.2m/min. A new crystallizer depended on thermo analysis was put forward,which was a crystallizer technology with an inner cooling apparatus.The function of setting inner cooling and deflected nozzle were analyzed, which indicated that the crystallizer with an inner cooling apparatus could improve heat transfer efficiency, reduce center segregation, form level swirling flow ,uniform steel component and growing of the shell, reduce the impact depth, achieve the metallurgical effect of electromagnetic stirring. Calculation results show that the crystallizer with an inner cooling apparatus may reduce the liquid core depth and infrastructure fee of caster.
    Real-time Energy Management of a Dual-axle-driven Off-road HEV Based on Willans Line
    Kan Ping, Qiu Lihong, Qian Lijun, Wang Jinbo
    2016, 27(11):  1546-1553. 
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    In order to achieve the real-time energy management of an off-road HEV, the dynamics models of the power components were built. A method was proposed based on the Willans Line models of engine and motor, and the optimal output power models of the engine and motor were built based on the WL-ECMS. HIL experimental results show that the WL-ECMS-based strategy can realize the basic energy management of the off-road HEV, and the velocity errors are kept within a desired range. The hundred kilometers fuel consumption with WL-ECMS strategy is only 3.03% more than that of ECMS and 12.07% less than that of the rule-based strategy. Furthermore, the computational time for a single step is reduced to 1.65 from that of 100 with ECMS, and it is comparable with the 1.07 of that of the rule-based strategy, thus the real-time energy management of the off-road HEV is realized.
    Study on Objective Evaluation Index of Vehicle Minimum Time Maneuver
    Zhang Lixia, Lu Jun, Pan Fuquan, Song Nianxiu
    2016, 27(11):  1546-1553. 
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    To evaluate the vehicle minimum time handling and stability, a comprehensive evaluation index of vehicle minimum time handling was proposed by adding the single factor evaluation index of speed and adhesion performance, considering the evaluation index of driver’ s busy, roll, sideslip. The double lane change test for vehicle was simulated with ADAMS/Car. The simulation results for the index values of single factor evaluation and comprehensive evaluation of vehicle minimum time handling were achieved. Moreover, the comprehensive evaluation index values of the handling and stability were compared under different initial speeds of the vehicle to complete double lane change test. The results show that both of the index values of single factor evaluation and comprehensive evaluation increase with time. The comprehensive evaluation index value of the minimum time handling and stability increases with the initial speed increasing, and the handling and stability are weakened.
    Research on Vehicular Rollover Warning Based on Improved TTR Algorithm
    Chu Duanfeng, Cui Jian, Deng Zejian, Tian Fei, Wu Chaozhong,
    2016, 27(11):  1557-1561. 
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    The TTR method might realize vehicle rollover warning, but there existed some problems(i.e. premature warning, hysteretic warning), because rollover threshold was difficult to precisely set up due to changing traffic conditions. In order to improve the traditional TTR method and the effectiveness of vehicle rollover warning, three degrees of freedom of vehicle dynamics model was established. A rollover evaluation index was proposed by using the relative value, i.e. ratio of immediate lateral acceleration to the real time lateral limit acceleration, instead of absolute value such as roll angle or lateral acceleration for rollover warning. According to the current vehicle dynamic states, TTR value in the forthcoming was calculated in real time. Finally, based on the improved TTR, the criticality of rollover threat in the forthcoming was predicted, and the vehicle rollover warning was achieved. The results show that comparing with two traditional TTR rollover warning algorithms, the improved TTR rollover warning algorithm may be used to predict rollover more precisely.