Table of Content

25 February 2016, Volume 27 Issue 04

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Posture   Coupled  Optimization  Control of  Wheel-legged  Robot

Xu Yan, Duan Xingguang

2016, 27(04):  427-432. 

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When wheel-legged mobile robots moved in uneven terrains,three basic non-isolated control problems such as stability control,drive traction control,and posture control were produced.Herein kinematic model with wheel-legged mode  was   established  firstly, which was suitable to describe the robot posture. Then stability and traction functions were addressed.In order to have good adaptability, high maneuverability of  negotiation and high locomotion security,coupled optimization function was built and coupled optimization control  was realized based  on  the comprehensive analyses of the stability and traction characteristics,which could supply the coupled optimization criteria for stability and traction,and realize the posture optimization control of the robots. The effectiveness of  the method was confirmed by experiments.

Rolling Bearing Fault Diagnosis Method Based on LMD Multi-scale Entropy and Probabilistic Neural Network

Meng Zong, Hu Meng, Gu Weiming, Zhao Dongfang

2016, 27(04):  433-437. 

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A rolling bearing fault diagnosis method was studied based on LMD multi-scale entropy and probabilistic neural network. In this method, the fault signal was decomposed into several product functions adaptively, and then the multi-scale entropies of each component were feed into the probabilistic neural network as fault feature vectors for pattern recognition to realize the diagnosis of damage position and damage degree. Comparing with the method based on LMD time-domain statistics and probabilistic neural network, the experimental results show that the method based on LMD multi-scale entropy and neural network can identify and diagnose the rolling bearing fault accurately and efficiently.

CNC System Software Reliability Estimation Based onWeighted Combinational Models

Wang Lichao, Han Jiang, Zhang Kuibang, Xia Lian

2016, 27(04):  438-444. 

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According to the problems of weak adaptability of single model, a method for CNC system software reliability estimation by using weighted combinational models was proposed. Firstly, three weighted combinational models, namely weighted arithmetic, weighted geometric, and weighted harmonic combinations, were proposed according to the characteristics of CNC system software. Secondly, the improved genetic algorithm was adopted to solve optimal weights for model combinations. Lastly, CNC system software failure data was taken into the models to estimate the faults of system, and then the estimation of CNC system software reliability was completed. Experiments were performed based on four sets of software failure data, and numerical results show that the weighted combinational model has a greater adaptability than that of single models. Then, the proposed models were applied to a self-developed handheld CNC system, and results verifies the feasibility and validity of the proposed method.


A Processing Algorithm of Non-orthogonal Signals for Micro-cantileverVibration Interferometry Measurement

Hubei University of Technology, Wuhan,

2016, 27(04):  444-448. 

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This paper designed interference measurement system which the stripe shape was less sensitive to cantilever's changing angles. Then analysing the characteristics of two-photoelectric receiving interference signals which were difficult to guarantee orthogonalization, a real-time ellipse fitting method was proposed. Using the  ellipse fitting method and the  conversion results, the theoretical formula of interference fringe phase change could be derived. Finally, according to the relationship between the phase and vibration displacement, and the property of vibration displacement's continuity, vibration displacement quantity could be obtained by using unwrapping algorithm. The results show that this method can achieve measurement level of interference precision order without additional hardware processing circuit wnder the conditions of the  sufficient sampling frequency.

Analyses  of Schnabel Car's Parallel Lifting Mechanism and Experimental Research on Electro-hydraulic  Weighing

Zhao Yanzhi, Wang Xiangnan, Ren Yubo, Bai Xuegang, Fu Yong, Wei Hongliang

2016, 27(04):  449-454. 

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In order to solve the precise weighing problem of long-heavy  cargo railway transportation schnabel car,the freedom of the parallel lifting mechanism was analyzed based on spatial closed loop.The coordinate transformation method of kinematic analysis was performed on schnabel car lifting mechanism,and the mapping model between lifting track of cargo and protrudent length of cylinder was established,the promotion mechanism of Jacobian transfer matrix system was obtained. Combined with the static equilibrium equation,the mapping model between output pressure of cylinder and mass of cargo was established.The  influences of structural deformation and cylinder friction on the parallel lifting mechanism  weighing precision  were analyzed and calculated;then the prototype of the schnabel car parallel lifting mechanism and its electro-hydraulic weighing test system were designed and developed. The experimental study on electro-hydraulic weighing was carried out based on friction compensation of schnabel car, and the weighting precision of schnable car  is improved.

Development of Strength Test Machine for Marine Emergency Towing Arrangements

Su Shijie, You Youpeng, Tang Wenxian, Li Cunjun

2016, 27(04):  454-460. 

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A test method of strength test for emergency towing arrangements was presented herein. In order to simplify the structure of test machine, the fairlead and towing pennant/chafing chain were rotated 30 degrees, so that the tensile plane was horizontal, and the strong point was tested separately, then the test procedure was presented. According to the test method, type test and factory test criteria, the work such as total design,steel-concrete composite body design, synchronous loading system design and towing pennant holding fixture design were completed. The strength test machine was developed, which consisted of the T type base platform and various holding fixtures. Using the test machine, strength test of a 2MN type  aft emergency towing arrangements we carried out. The practices show that the test method is feasible, and the test machine has some features such as reasonable structure, good reliability and high precision, etc.

Modeling and Analyses of Rigid-flexible Coupled Structural Dynamics for Offshore Floating Wind Turbines

Peng Chunjiang, Hu Yanping, Cheng Junsheng, Shen Yiping

2016, 27(04):  461-468. 

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A rigid-flexible coupled structural dynamics model was established for offshore floating wind turbines with three-bladed horizontal-axis-rotor based on Kane method combined with the mode superposition method. Firstly, the hydrodynamic load model was determined. Then, the flexible members such as tower and blades of wind turbines were discretized into multiple rigid unit. Partial velocity and partial angular velocity of each discrete element were expressed by using the mode superposition method. Last, the rigid-flexible coupled structural dynamics model was derived based on above work by using Kane method. The dynamic responses of  the NREL 5-MW offshore baseline wind turbine were calculated using the established model along with the aerodynamic model and the hydrodynamic model. The output power, coupled characteristics of offshore floating wind turbines were compared with onshore's.

Dynamics  Model and Balanced Pitching Control of a Unicycle Robot

Zhuang Wei, Liu Chengju, Jiang Han, He Shutong

2016, 27(04):  468-474. 

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Dynamics of a three driven joints' unicycle robot and controller to achieve the robot's balanced pitching motion  were  disscused herein.Firstly,considering the coholonomic constrain between the running wheel and the ground,a dynamics  model for the unicycle robot  was  established by using  Chaplygin equation.The model reveals there are 6 generalized  velocities and  3 underactuated freedoms in the robot system. Secondly,focusing on the dynamics subsystem of the robot's balanced pitching motion, and  a controller for this kind of motion was developed. The controller was based on the partial feedback linearization method, which linearized the underactuated pitching angle,and took the pitching  angle  and  the rotating angle of the running wheel as outputs.The  numerical simulation and prototype experiments were  performed to testify the validilities of the proposed controller.

Development of Mine Hoist Constant-deceleration Emergency Braking System with Software and Hardware Redundant Design

Huang Jiahai, Guo Xiaoxia, Quan Long, Zhao Ruifeng, Li Wenyong, Ma Huijun

2016, 27(04):  475-478. 

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Constant-deceleration emergency braking system was considered as the ultimate security measure of a mine hoist. It was of great significance for safety and reliability of the mine hoists. Aiming at the shortcomings of the present constant-deceleration emergency braking system, a constant-deceleration emergency braking system was presented herein based on software and hardware redundant design. In this system, the faulty circuit was replaced synchronously in real-time by the spare one because the hot spare was adopted in the redundant design. The numerical and experimental results under unloade show that the scheme is feasible. They also show that the speed tracking error at the early stages is higher than that at the last stages because of the nonlinearity, time-varying and delay.

Fault Diagnosis  Method  for Wind Turbine  Vibration Based  on  Improved  Negative  Selection  Algorithm

Wu Chunming, Yin Haiyan

2016, 27(04):  479-482. 

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In order to correctly judge wind turbine vibration fault types,reduce  its impacts  on power generation efficiency and personal property safety,this paper proposed  an improved algorithm.In the traditional negative selection algorithm  Mahalanobis distance  was introduced for preliminary screening of vibration data,and the prediction   algorithm was applied to the wind turbine vibration faults.At the same time with the  two algorithms the diagnostic accuracy of fault diagnosis  was  improved.Studies show that the improved negative selection algorithm can be more quickly and accurately determine the fault type units and the diagnostic accuracy of 97.5% are achieved.And it can improve the wind turbine operation reliability and power efficiency.

Simulation  Analyses  and  Experimental  Investigation on  Optimum Matching of Operating  Parameters  of  Tower Mill

Xiao Zhengming, Wang Xin, Wu Xing, Long Wen

2016, 27(04):  483-487. 

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The existing researches on optimum matching of operating parameters of the tower mill were  insufficient, which affected  the development of the grinding efficiency and the engineering applications of tower mills.A  DEM  was used to simulate the main operating parameters of tower mill. Collision energy,collision frequency, power consumption and other physical quantities which were  related to the  grinding performance were studied.The effects of the operating parameters on  the aggregate  particle size were  obtained  through the experiments  and the accuracy of the simulation analyses was verified. The results show that, under the critical speed, the higher the speed  the better  the grinding efficiency  and the optimal speed of the tower mill is  210r/min;if  the filling rate is  so low   that the grinding strength will also  be low, if the filling rate  is  so  high  that the energy  utilization rate will decline. Comprehensive consideration of the grinding strength and energy utilization rate, the optimal filling rate of the tower is as 60%.

Configuration Design and Applications of ControllableLoader Mechanism Based on Graph Theory

Zhang Lin, Cai Ganwei, Zhu Kaijun, Li Junming, Wang Xiaochun

2016, 27(04):  488-493,502. 

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A comprehensive and systemic configuration design and reseach of  a new type loader work equipment were completed based on graph theory and other related theory. Using the technique of embryo graph vertex insertion configuration synthesis was carried out on two-DOF plate closed-loop mechanism within 9 members and only one hinge revolute joint, and then  51 kinds of topology graphs were obtained. According to the controllable loading mechanism's requirements of structures, functions and constraints, and principles of minimalist topology,  topological synthesis was realized on those 51 topology graphs.  22 kinds of topology graphs meeting the configuration requirements were found. Then according to proposed existence conditions of frame, bucket and boom all topology graphs were specialized. In the end, the optimization principle of loading mechanism was proposed, the scheme of specializing topology graphs were prefered. So 11 kinds of controllable loading mechanisms were obtained. Through developing a prototype based on one kind of those mechanisms, its working performance meets design requirements. This study provides a configuration basis for design and developing a new type controllable machinery loader.

A Hybrid Discrete Particle Swarm Optimization Algorithm for Vehicle Routing Problemwith Time Windows and Simultaneous Pickup and Delivery

Hefei University of Technology, Hefei,

2016, 27(04):  494-502. 

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Considering the relative importance of dispatching cost of vehicles and travelling cost of routes, a mixed integer mathematical formulation of the vehicle routing problem with time windows and simultaneous pickup and delivery (VRPTWSPD) was established to make the total delivery cost, the number of vehicles and the travel cost minimize simultaneously. A hybrid discrete particle swarm optimization algorithm was proposed for solving VRPTWSPD. Solutions of algorithm were represented by an intuitive fragment-free giant tour of a permutation of all customers, and were decoded and evaluated by the revised depth first search split procedure. A variable neighborhood descent search procedure was carried out under a certain probability for individuals at each iteration, so that individuals could update with depth search in multi-neighborhood and with bread search in global exploration. The simulated annealing idea and mutating a selective portion of worst individuals were applied to improve the stagnation of the search. The feasibility and effectiveness of the proposed algorithm were verified by two instances with different goals.

Design  Principle  of  Magnetorheological  Force  Limited  Seatbelt

Zhao Xiaoyu, Wang Xiaocong, Wang Yansong, Wang Jianong

2016, 27(04):  503-507. 

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An  active limiter for seatbelt constrain  force  with MRF was  proposed.This MRF force limiter was designed in order to avoid having a harmful effect on human body when seatbelt emergency locking.The control principles and structure for MRF force limiter  were  proposed.To research corresponding relationship between the limited  damping force and external control current the magnetic saturation analysis method was adopted.Limiting value of limiter  was set up according to chest load-carrying capability,and its feasibility was verified by a numerical example. The MRF  force  limiter  can be used with emergency locking retractor. It can realize intelligent control and  reuse.

Cutting Force Model  and Experiments  of Single Crystal Silicon under Diamond Fly-cutting

Yan Yanyan, Wang Runxing, Zhao Bo

2016, 27(04):  507-512. 

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The  processing  characteristics of single crystal silicon under diamond fly-cutting were analyzed herein,and the mathematical model for the undeformed chip thickness and the theoretical determinant criteria which may distinguish the types of materials removal were built separately,then the mathematical prediction model of the cutting force was established, which befits both the traits of diamond fly-cutting technology and the material properties of  single crystal silicon, finally the cutting forces were measured through the cutting orthogonal experiments  of the silicon wafer under the diamond fly-cutting.As a result, the rationality of cutting force  model  was  proved by comparing the  calculated values and the experimental measured values of cutting force, meanwhile, the influence rules of the largest undeformed chip thickness hmax  and the main working parameters on cutting forces were summarized based on the experimental  results.

Analysis of  Influence of Cutter Diameter on  Mechanics Propertiesof Shrink-fit Holder and Cutting Tool

Liu Bo, Zhou Houming, Zhou Youhang, Zhang Gaofeng, Peng Ruitao

2016, 27(04):  513-517,525. 

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Based on the theoretical analyses of matching molder between shrink-fit holder and cutter, the mechanics properties of the matching such as contact pressure, equivalent stress, thermal deformation and thermal strain were analyzed at different external diameters of shrink-fit holder in static, under radial force and inducting heating by using the finite element software ANSYS. The results show that the total contact pressure, maximum equivalent stress and thermal stress increase and the minimum thermal displacement difference decreases with the increase of holder external diameter. Under the action of radial force, the contact stresses on the holder no longer uniform and the maximum contact stress significantly increases, cutter also deforms. Finally a method to determine the reasonable holder external diameter is given and it has a practical guiding significance for the design and selection of the shrink-fit holder.

Simulation Analysis on Suspension Characteristics and DecouplingControl for Dust-free Transit System  Using Permanent Magnetic Suspension

Jin Junjie, Duan Zhenyun, Sun Feng, Lu Yingyuan

2016, 27(04):  518-525. 

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This paper proposed a dust-free transit system using permanent magnetic suspension. In this transit system, four non-contact suspension supports  were arranged in two lines symmetrically using active permanent magnetic suspension technology.In each suspension support, the disk permanent magnet driven by a servo motor produced  the magnetic force and the magnetic suspension force between the support and the iron guide rail  was  controlled in real-time. This paper gave  the dynamics   model after eliminating redundancy control points of suspension force, and analyzed  the suspension characteristics of undecoupled system by numerical simulation using LQR control method. The simulation results indicate that the transit system is coupled and not easy to control. Moreover, the numerical simulation was done with the state feedback decoupling control strategy. The results show  that the decoupling control strategy improves the control characteristics of the transit system, which has a good stabilities and response characteristics.

Test  and 1D/3D Co-simulation of Thermal Management for  a  Commercial Vehicle Engine Compartment

Guo Jianzhong, Luo Renhong, Wang Zhifeng, Hu Li, Wu Yong

2016, 27(04):  526-530. 

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In  order  to  solve  the problems  of engine outlet water  high temperature at rated power conditions.3D,1D  and  1D/3D co-simulation  tools were  used  to analyze the characteristics of heat dissipation in the engine compartment and the performance of cooling system  respectively.Comparing the results of  1D/3D co-simulation and bench test,the results show the simulation results are in good accordance with test data,so  the simulated model is reliable.At the same time,appropriate measures for improvement to avoid the thermal reflow phenomenon in a commercial vehicle engine compartment were proposed, then the road  test was carried out.It shows  that the measured outlet coolant temperature of engine reduces by 37℃, the effectiveness of the  improved  program
is verified. By the 1D/3D  co-simulation, the analysis efficiency of the underhood thermal manage can be improved greatly, the development cycle will  be reduced.

Effects of Intense Cooling on Deformation and Residual Stresses for FSWed TC4 Titanium Alloy

Ji Shude, Wen Quan, Lü Zan, Yang Zhanpeng

2016, 27(04):  531-536,543. 

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Choosing 2 mm thick TC4 titanium alloy plate as the research object, temperature field and buckling deformation of FSW were simulated by the ABAQUS software under conditions of air cooling and intense cooling. Meanwhile, the results of simulation were verified by experiments. Results show that the distribution of temperature field is of ellipse shape during welding process. The longitudinal stress perpendicular to the weld presented bimodal type. Compared with air cooling condition, the intense cooling decreases the peak temperature, narrows the distribution range of high temperature and reduces residual tensile stress in the surface where the reducing effect is greater than that in the bottom. The saddle shape deformation of welding plate under intense cooling condition is equivalent to 72.2 percent of that under air cooling condition, when the strength and distance of intense cooling are as -30 ℃ and 20 mm respectively.

Study on Distribution of Initial Residual Stress in 7075T651 Aluminium Alloy Plate

Liu Liangbao, Sun Jianfei, Chen Wuyi, Chen Qingliang

2016, 27(04):  537-543. 

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A modified layer-removal method was proposed to measure the profile of residual stress within the material by analyzing the characteristics of a traditional layer-removal method. The proposed approach estimated residual stress fields by the combination of measuring strains on the bottom of specimen and the coefficients of strain release using the finite element method (FEM) simulation. The initial residual stress was then deduced by revising the measured stress based on the elasticity theory. Furthermore, the residual stress in a 7075T651  aluminium alloy plate was measured using the proposed method, and the results were then analyzed and compared with the data obtained by the traditional methods. The analyses indicate that the modified layer-removal method is effective and practical for measuring the residual stress distribution in pre-stretched aluminium alloy plates.

Microwave Molding Process  for  Facesheet-reinforced Spacer Fabric Composite Component

Yuan Tiejun , , Zhou Laishui , Zheng Weifeng , Tan Changbai

2016, 27(04):  544-548,554. 

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In order to solve the problems of excessive consumption time and difficulty keeping high piles vertical  in facesheet-reinforced 3-D spacer fabric composites component(FSFCC) molding process, laying process keeping high piles vertical was presented. Core molds used in  above-mentioned laying process were designed. The special curing method composed of five measures with microwave heating was designed. These measures were as follows: using high thermal conductive and wave-transparent core molds; applying proper curing pressure; using multi-layer dissimilar material mold;using customized microwave oven;adopting multiple ramp rate. FSFCC samples were made on the basis of the molding process. Mechanics properties of experimental FSFCC samples were tested. Flexural stiffness, flatwise compressive strength, flatwise tensile strength and tensile shear strength are 20.0N·m2, 2.2MPa,3.3MPa and 0.60MPa respectively. Making one specimen with size of 30cm×14.5cm only cost 2028 kJ power. So conclusion can be drawn from experimental results that molding process presented herein can be used to make FSFCC with vertical high piles and good mechanics properties at the cost of less energy efficiently.

Research on Automotive Transient Crosswind Stability Based on DiscreteAerodynamic Coefficients

Yang Jianguo

2016, 27(04):  549-554. 

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The motion vector relation of a car was built under the action of crosswind in general case, a multi-body  dynamics model of the car was established by using ADAMS Car. Based on the external flow field analyses of body, the discrete aerodynamic six-component coefficients were translated into continuous aerodynamic forces by using the vector relation, the crosswind load was exerted in real time according to yaw angle of body; the transient crosswind stability simulation was executed according to ESV regulations.The influence rules of simplified aerodynamic load on crosswind stability were discussed, the quantitative simulation results are agree with the flow field qualitative analyses, which proves the correctness and reliability of the method.

Reliability Sensitivity for Main Reduction Gears of a Car Based on Response Surface Methods

Liang Mingxuan, Wang Xiaolin, Yuan Huiqun, Yu Yinxin

2016, 27(04):  555-559. 

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In order to obtain the effects of size parameters on reliability of the main reduction gears in a car, an improved LHS was presented to acquire the random size samples. The full quadratic RSM of the maximum contact stress on tooth surface was built through explicit finite element simulations to study reliability sensitivity to the key parameters. The results show that the mean and variance of pressure angle and modulus which are more sensitive to reliability of the gears must be selected reasonably in design stage.

Exact Linearization and Feedback Control of Semi-activeConnected Hydro-pneumatic Suspension

Cao Xuyang, Cao Linlin, Wang Dianlong

2016, 27(04):  560-567. 

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Based on differential geometry theory, the nonlinear system was transformed to a linear one, and the linear feedback control system of semi-active connected hydro-pneumatic suspension was done. With the software AMESim and MATLAB/Simulink, the co-simulation model of semi-active connected hydro-pneumatic suspension was completed. The simulation results show that the semi-active connected hydro-pneumatic suspension improves the property of upper vehicle, which decreases the stable time of instantaneous impact and the maximum values of instantaneous impact and enhances the ability of vibration damping and overturning resistance. Moreover, it improves suspension dynamic flexibility, which makes the suspension vibrate more smoothly and reduces the instantaneous vibration intensity.