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2009 Vol. 35, No. 2

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New technique of contour adjustment for high precision reflector panels
Zhou Xianbin, Hao Changling, Li Dongsheng, Li Xiaoxing
2009, 35(2): 127-131.
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The high precision of antenna reflector panels is the key to develop the technique of high performance compact antenna test range. A new technique of contour adjustment for high precision sandwich reflector panels was developed. The principle of the contour adjustment of panels was analyzed. The core technology problems such as the decision of adjustment points- position and number, the adjustment value on each points were proposed. By use of numerical simulation, how many and where the adjustment points should be were determined. The algorithm for adjustment value calculation was verified by experiments. A contour adjustment device was designed and developed. Numerical simulation and experiments of contour adjustment were conducted against all possible shape error distribution. The results show that, by use of the adjustment device and the proposed core technique, the contour of panels can be adjusted effectively and the contour precision can be improved greatly. Additionally, contour adjustment technology makes it possible to use for the panels with bigger size and higher contour precision, to increase the qualified rate of finished product obviously and to improve the maintenance performance of reflector panels.
Microstructure and property analysis of 0Cr18Ni9Ti joints welded by ultra-sonic pulse tungsten-inert-gas welding technology
Qi Bojin, Xu Haiying, Zhang Wei
2009, 35(2): 132-136.
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An ultra-sonic pulse tungsten-inert-gas (TIG) welding power source based on new type IGBT topology was developed. 0Cr18Ni9Ti austenitic stainless steel workpieces were welded by ultra-sonic pulse TIG welding and conventional direct current TIG welding respectively. In order to study the difference between joints welded by different welding technology, these weld joints were analyzed by means of X-radial check-up, tensile strength and specific elongation detection, optical-microscope and scanning electron microscope. With the ultra-sonic pulse TIG welding technology pulse current frequency being increased, it can be found that grains will be refined and the width of the coarse grain zone will be narrowed, correspondingly, small equiaxed grains zone will be enlarged. By contrast with conventional direct current TIG welding technology, these joints introduced by 30kHz ultra-sonic pulse TIG welding technology, have more small equiaxed grains in weld joints core, which indicates grain refinement phenomenon is distinct. The tensile strength and the specific elongation of these joints welded by 30kHz ultra-sonic pulse TIG welding technology were improved respectively.
Human-computer interaction technology of virtual assembly system for complex products
Zhao Gang, Wang Chao, Hou Wenjun, Jin Yue
2009, 35(2): 137-141.
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Based on the dual computer synchronized desktop virtual reality equipment, a virtual assembly system for the complex products was introduced. The human-computer interactive technology in the system was studied. The product information management technology was proposed on an algorithm of the SOP (structure of parts) data construction which acted on the attribute class for driving. The DOF (degree of freedom) law for matching the rotation center of models was presented. A direct and fast control interactive algorithm principle which was suitable for the multi-parts and multi-scenes grounded on the LOS (line-of-sight) technology was discussed, and the usability and efficiency of the algorithms were verified through the system realization. It is proved that the performance and extension feature of the system were promoted obviously.
Static tensile crack behavior of brazed joints of dissimilar metals tubes in aerospace system
Qu Wenqing, Lu Jiehong, Zhuang Hongshou
2009, 35(2): 142-145.
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The dissimilar metals(such as Titanium alloy and stainless steel) thin-wall small-diameter tube structrues in aerospace propulsion system were bonded, using high frequency induction brazing process. Their qualities and properties are largely superior to the bolt connection tubes structures. The static tensile experiments of the brazed joints were conducted. The results indicate that the mechanical properties of joints brazed using Ag-based filler metals are slightly better than those using Cu-based filler metals. And then the joints microstructures after static tensile experiments were analyzed. It is found that, all the cracks in the joint area brazed by Ag-based filler metals germinate and propagate in the brazing seam, the cracks stop when they propagate on the interfaces between brazing seam and the base metals. The cracks in the joint area brazed by Cu-based filler metals germinate in three locations: the boundary of two phases in the brazing seam, the interface between brazing seam and Titanium alloy, the interface between brazing seam and stainless steel. The crack driving force consistes mainly of the static tensile load and the mismatch behaviour of dissimilar metals brazed joint. And the resistance force of crack extension is related to the microstructures in the brazed joint.
Analyzing and controlling distortion of aircraft aluminium alloy structural part in NC machining
Mei Zhongyi, Gao Hong, Wang Yunqiao
2009, 35(2): 146-150.
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NC machining distortion and the reason which leads to machining distortion were studied by analyzing the typical aircraft wing rib aluminium alloy structural part on which distortion often occurs. The part NC machining distortion was analyzed and compared by using the methods of theoretical model, finite element analysis and milling experiment. Residual stress distribution was analyzed in the part. Temperature simulation was added to the residual stress distribution of aluminium alloy by using thermal-mechanical coupling analysis of the FEM(finite element method) software. The influence on part distortion by cutting material was analyzed and simulated. The cutting process was simulated and improved through using the improving static elements deactivation method. Simulation distortion result of machining process was compared with the milling experiments and practical experience data. The validity of the analysis method and the finite element analysis model was verified. Several methods which can be used to predict and control machining distortion were proposed.
Forming press and spring-back analysis of curving sandwich structure
Guan Shiwei
2009, 35(2): 151-153.
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Aiming at the mechanics problem during the manufacture process of curving sandwich structure, the changes of the bending stiffness were analyzed, the forming theories were explained and the calculation formulas of bending stiffness were found. By discussing the calculation method of the forming pressure about the microcurving rate curving sandwich structure and using the plate theory, the calculation formulas of the forming pressure about the microcurving rate curving sandwich structures, including the examples and the results were deduced. After discussing the calculation methods of the spring-back about the curving sandwich structures, the calculation formulas of the spring-back about the curving sandwich structures and the results of the calculation examples were presented. Based on the characteristics of the deformation about the common honeycomb, the flexibility honeycomb and the micro-turss structures, the principles of choosing the curving sandwich structures core were also presented.
Experiment of sheet metal on laser bending
Cai Yougui, Wang Xiufeng, Chen Guangnan, Jurgen Silvanus
2009, 35(2): 154-157.
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The process of laser bending for aluminium alloy AA6056 used to produce large airplane panel was studied through experiment. The thickness of specimens was selected 1.0 mm and 2.5 mm separately. The different groups of the technological parameters were used to analyze contrastively in the process of laser bending. The specimen was clamped at one end as a cantilever plate and was irradiated by the laser beam in the width direction. 0.1 mm diameter NiCr/NiSi thermocouple was adopted as temperature sensor in the experiment, and the temperature on the specimen surface was measured by YOKOGAWA MV200 measuring device. A free end point was chosen as a measuring point and a CCD-camera recordsed its displacement during the laser bending process. The video was processed by the measuring software, which was developed by Beijing University of Aeronautics and Astronautics, and the displacement value can be obtained. Experiment result supplies more accurate data for numerical simulation of laser bending process and provides the experimental foundation for research on laser bending process deeply.
Redundancy and hot swap technology in industrial Ethernet EtherCAT
Huan Ji, Xiao Wenlei, Liu Yanqiang
2009, 35(2): 158-161.
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EtherCAT is a type of real-time industrial Ethernet protocol for data communication in automation control system. Redundancy is an important way for hot swap and improving the communication reliability. The architecture, principle and frame structure of the EtherCAT were introduced. The fault tolerance and hot swap technology in EtherCAT based industry automation control system were proposed with ring topology. The master carries two full duplex Ethernet interfaces, forming two logical data stream. If there is a failure in the link, the EtherCAT slave will automatically loop back the data frames, so the ring topology is fault tolerant for one point failure. Redundancy frame transmission mechanism, fault location and recovering for network interface failure, link broken and node failure were laid out. The EtherCAT master driver with link redundancy was developed by adding the redundancy control to the normal EtherCAT master driver. It proves that the system is robust and has excellent performance of redundancy and hot swap function.
Elastic constant matrix measurement of SiCp reinforced aluminum metal matrix composites
Zhou Zhenggan, Gao Yifei, Lü Yan, He Fangcheng
2009, 35(2): 162-165.
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In order to reveal the relationship between SiCp volume content and mechanical property of SiCp reinforced aluminum metal-matrix composites (MMC) fabricated by powder metallurgy, the elastic constant matrix of the standard samples with different SiCp volume content were measured with elastic wave method. The relationship between the velocities of ultrasonic waves travelled in the material and the elastic constant matrix was deduced with Christoffel equation in transverse isotropy model. The basic principle of velocity measurement of quasi-longitudinal waves and quasi-transverse waves with the oblique incidence immersion method was introduced. The experiments based on the above mentioned principle and method were carried out and the elastic constant matrixes of the standard samples were calculated out. The results show that the mechanical property of material in the extrusion direction is better than the other directions, and with the increasing of SiCp content, the elastic constant rises and the intensity of the material enhances.
Basal worm-designing method of face-gear hob
Wang Yanzhong, Wu Canhui, Ge Xuyang, Zhang Li
2009, 35(2): 166-169.
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Face-gear drives become the main direction of research for aeronautical drives because of their special advantages. The applied coordinate systems of face-gear were set up and the equation of face-gear tooth surface was established, then the face-gear tooth surface constrain conditions for dedendum undercutting and addendum pointing were analyzed based on the face-gear transmission theory, at the same time, the disciplines were discussed on the relationships between pressure angle and the face-gear outer & inner radius in keeping with the practically calculated examples. The calculating results are useful for designing the face-gear drive. In the end, the face-gear hobbing theory was analyzed, according to the gear geometry and applied theory, the hobbing surface equation was founded. The discrete values of three-dimensional coordinates for the hobbing surface were calculated by using the method of numerical calculation. The three-dimensional basal worm model of face-gear hob was designed by recurring to the three-dimensional software.
Modified Grangeat algorithm as apply to a circular scan orbit
Wei Dongbo, Zhang Likai, Fu Jian
2009, 35(2): 170-173.
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To compensate for artifacts in reconstructed images of industrial computed tomography (ICT), Grangeat type exact cone beam reconstruction algorithm was studied. Grangeat algorithm based on flat detector was implemented by the steps of computing first partial derivatives of cone-beam projection data along rows and lines respectively, first partial derivatives of Radon data, back-projection and so on. Due to the missed data of a circular scan orbit, the incomplete Radon space was analyzed. The nearest-neighbor interpolation, linear interpolation, 3-points quadratic interpolation and one-dimensional linear regression interpolation methods were used to estimate missed data respectively, and the effects of different methods on the image quality were examined. The compute simulation results prove the validity of proposed methods.
Modeling and finite element analysis of thermal barrier coatings in IR NDT
Guo Xingwang, Ding Mengmeng
2009, 35(2): 174-178.
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The transient heat conduction of TBC(thermal barrier coatings) structures in TNDT(thermal non-destructive testings) was described by an axisymmetrical model in a cylindrical coordinate, and the corresponding physical model was constructed. The temperature field of TBC structures stimulated by a heating pulse was analyzed by using the FEA(finite element analysis) software ANSYS, and the relations between information parameters(such as maximum differential temperature and maximum contrast) and defect parameters(such as defect radius, depth, coating thickness and thickness difference) were studied. The results show that, at a fixed coating thickness, the maximum differential temperature and maximum contrast are a nonlinear function of the defect radius respectively and increase with the defect radius, and their saturation value exist. At a fixed defect radius, the maximum differential temperature and maximum contrast are a nonlinear function of the coating thickness respectively, and decrease when the coating thickness increasing. These results provide a theoretical support for the detection and characterization of delamination in TBC structures by infrared thermography.
Experimental analysis of minimal quantity lubrication in milling high-strength steel
Yuan Songmei, Liu Xiaoxu, Yan Lutao, Liu Qiang
2009, 35(2): 179-182.
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In order to validate the influences that MQL(minimal quantity lubrication)brings to the tool wear and surface roughness, a MQL system was developed. It used the difference of pressure that caused by the compressed air flow through the decrescent areas to imbibe the cooling fluid in the box, and transported it to the nozzle for atomizing. The application in milling high-strength steel was also investigated. The experiment indicates that MQL has obvious predominance compared with dry and traditional cooling method, it can efficiently reduce the tool wear and keep the surface roughness at a low level, especially in the machining of high spindle rotating speed,big depth of cut and fast feed rate. It also has the characteristics such as the simple structure, the less dosage of cooling fluid and the less pollution to the environment. The experimental results were analyzed elementarily.
Dynamic analysis of lunar lander
Wang Chunjie, Guo Yong
2009, 35(2): 183-187.
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By the modal analysis of lunar lander based on MSC.Patran/Nastran, the main factors affecting the mode frequency were retrieved, including the dimensions of the machine and the method of the assembled part. The influence brought about by modifying the thickness of the piston barrel and piston rod on the mode frequency was illustrated. Meanwhile, the connection method of the assembled part was also studied. Subsequently a new approach based on Bush was proposed to solve the problems encountered by using MPC(multiple point constraint), which makes the simulated results more accurate. Finally, frequency analysis on the stow model of the lunar lander was implemented, whose result shows the structure can not resonated in the specified range of excitation, which further validates the reliability of the lunar lander.
Finite element simulation of machining deformation for aeronautical monolithic component
Zhang Yidu, Zhang Hongwei
2009, 35(2): 188-192.
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Machining deformation has been a bottle-neck issue in aeronautical manufacturing field. Based on finite element simulation, the influence of original residual stresses on the deformation in the process of machining for aeronautical monolithic component was studied. The redistribution law of residual stresses during machining and the trend of deformation change were analyzed. The simulation conclusions agree with experimental results. The machining deformation characteristics due to residual stresses were analyzed and the simulation of different machining path was carried out. The results indicate that the research on deformation caused by residual stresses alone can neglect the effect of machining path. The coupling effect between residual stress and milling force was taken into account and the simulation was performed for different machining path.
Topological modeling system of engineering CAD based on template data library
Liu Jinghua, Wang Lei
2009, 35(2): 193-196.
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Topological pipe-net models of engineering CAD were established using templates data library. The topological templates data library was constituted of many topological models each of which was abstracted from engineering object and had its unique characters. The loosely coupled three-tier architecture system that was applied to model pip-net models of engineering CAD was designed based on topological templates data library. The system included three layers: user layer, templates data library management and data layer. The templates data library management provided convenient and instant management of topological templates, and consequently the establishment and maintenance of pipe-net templates became more efficient. The data layer provided common data interfaces and thereby the topological templates data from different fields could be shared. The system hierarchy is clear, and the dependent relationships between system models are fewer, and especially it is easy to be realized. The efficiency and compatibility of pip-net modeling in engineering CAD field can be greatly improved using this system.
Fuzzy recognition and object-capture algorithm for robot vision systems
Huang Rongying
2009, 35(2): 197-200.
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With reference to the object recognition process of human eyes and minds, the region segmentation and fuzzy recognition algorithms were established for robot vision systems in order to deal with the problem of the object-capture recognition. The gray-scale and chromaticity of images were taken as a basis for region segmentation and fuzzy recognition,the index of the characteristics were taken from gray-scale,chromaticity and body features,and the definition method for feature recognition on the basis of walsh transform meta-models was put forward with the sharp low-frequency gathering tendency of the gray-scale. Then,the recognition algorithms was worked out utilizing the fuzzy relation composition and maximum subjection according to the object recognition matrix and relation matrix was established.With the algorithms, the objects within small samplings spots can be recognized, which has practical values in the object-recognition in the capture control of robots.
Information modeling of product design process for virtual prototyping
Xiao Lifeng
2009, 35(2): 201-204.
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To control the various simulation models and design activities, the features of information modeling of virtual prototyping design were discussed, and an integrated information model was proposed. Product design object was abstracted as property unit of static and dynamic characters and operating unit. Virtual prototyping information model was expressed from product geometry, physics and behavior. Design process information model was formalized with the control of design tree object, design role object and resource configuration object. This information model was used successfully in the construction of distributed collaborative simulation environment (DCSE).
Distortion mechanism and mechanics performance of eggshell-like gore structure
Jiao Hongjie, Zhang Yidu, Chen Wuyi, Zhang Hongwei
2009, 35(2): 205-208.
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From the point of structure biomimetic, the model of eggshell-like thin core structure was put forward. From the test of model, the press distortion mechanism was concluded and the carrying capacity of egg-like thin shell core structure was depended on material, size and form angle. Applying thin shell theory, buckling critical load of eggshell-like under action of press load was counted out. In addition, limit element unit model was built up and mechanism and buckling mode were analyzed. The theory basis for weight reduction design was provided in engineering in future.
Evolution process of quality BOM for product process
Tang Xiaoqing, Hu Yun
2009, 35(2): 209-214.
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A method based on BOM (bill of material) was proposed to organize quality data throughout product process. Quality assurance process for product process was proposed, and then the characteristics of quality management for product process were ascertained. The definition of quality BOM was specified in quality domain. Data structure model for quality BOM based on object-oriented method was built. Evolution process of quality BOM for product process based on key quality characteristic chains was put forward. Evolution rules and methods for quality BOM composing of quality material item, quality configuration and quality feature were then analyzed. An integrated organization model for quality data based on quality BOM evolution process was put forward.
Application of online simulation in production planning and scheduling
Yang Jianjun, Kou Yi
2009, 35(2): 215-218.
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Several critical technologies of planning and scheduling including data modal, application frame of online simulation system and system integration were studied. The application of the object-oriented simulation system was proposed and implemented to solve the problems of system initialization and stochastic settings through online data exchange. It was discussed how to valid a shop floor production plan using online simulation, how to examine the robustness of a real-time production plan and how to readjust this plan. With the help of these results, reliable reference can be supplied for making decision on production planning in every period.
Architecture and accomplishment techniques of agile manufacturing data source
Qiao Lihong, Liu Wei
2009, 35(2): 219-222.
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To satisfy the agility requirement of manufacturing data management in product lifecycle management, an approach of agile source of manufacturing data (ASMD) for data management was proposed. Based on the analysis of the application requirement of agile manufacturing data, the ASMD was defined as architecture for manufacturing data definition and management to meet the constant change in application requirement in product lifecycle management. The architecture of ASMD was composed of four layers: core object and ontology layer, meta-data and meta-mode layer, service component layer and implementation layer. The characteristics of the architecture were discussed. Three techniques for ASMD implementation were presented, that is, abstract meta-modeling, fast data view generation based on rules and component reuse and reconfiguration based on service techniques. The ASMD provided a new way to support agile manufacturing data management and its applications in product lifecycle management. It can also be a way to promote the agility of information systems.
Ontology-based semantic similarity computation for maintenance CBR
Wen Jingqian, Li Qing
2009, 35(2): 223-226.
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CBR(case-based reasoning) finds solutions for new problems based on previous experience. It is suitable for such applications as aircraft maintenance knowledge acquisition, representation and reuse. With consideration of some special characteristics of aviation maintenance, such as spot recording, reliability analysis and fault disposal, firstly the classification and the relationship of the relevant maintenance knowledge and information were investigated, and then the definitions of domain knowledge and case knowledge of maintenance were provided. Ontology models for product structure, maintenance inventory, failure mode, failure causation, and data dictionary were developed and the consistency in the knowledge description was realized. The case model architecture and retrieval technique were studied in detail, and an ontology-based semantic similarity computation method was proposed and applied to maintenance case recall and match. The method combined the depth and out-degree as two main influences for the similarity of concept model. Finally, an aircraft maintenance knowledge management system was developed. An application example shows that the method can benefit the aircraft maintenance.
Method of multi-domain topology optimization for continuum structures
Guo Lianshui, Punit B, i
2009, 35(2): 227-230.
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To solve the problem of continuum-based structural topology optimization under large deformation loading, the hybrid cellular automata (HCA) paradigm for multi-domain topology optimization technique was proposed, a relative density-based material parameterization was developed to model both elastic and plastic material behavior. The state of each cellular automata (CA) was defined by the density and strain energy density, and the uniform strain energy distribution of each design domain was realized by modification the relative density in accordance with CA local control rules. The multi-domain optimization HCA algorithm and convergence strategies were also discussed, these strategies include the simultaneous design of multiple, coupled components and converged individually. An example of bumper structure was presented to demonstrate the results of the multi-domain HCA algorithm, the bumper generated by the HCA algorithm for reduce the peak of reaction force 54% at a suitable sacrifice of stiffness.
Hybrid location method for home service robot based on intelligent space
Wang Tianmiao, Tao Yong, Wei Hongxing, Chen Diansheng
2009, 35(2): 231-235.
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Based on the requirement of service robot operation in home environment, an intelligent space framework for service robot was proposed,which was composed of smart objects, RFID (radio frequency identification) tags, wireless access points, home server and a service robot. After that, the hybrid location method for home service robot based on intelligent space was given. The WLAN (wireless local area network) location based on RSSI (received signal strength indication) was introduced; then, analysis methods of the RFID decision-maker and vision location based on SIFT (scale invariant feature transform) were proposed. The integration of the three methods was proposed using the different features of the RSSI, RFID decision-maker and SIFT algorithms. Finally, the result was verified through experiment in home environment. With the help of intelligent space, the hybrid location method can provide a low-cost and reliable solution for the service robot entering families.
Super-harmonic resonance and complex movement analysis of flexible manipulator in temperature field
Yun Chao, Cui Yihui, Wang Wei, Tang Qing
2009, 35(2): 236-240.
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In order to study on nonlinear vibration of flexible manipulator, a mathematical model of mechanical system considering damping, material nonlinearity, temperature variation and axial excitation was established using the Garlerkin method. Furthermore, the adequate and essential conditions for homoclinic orbits, hetroclinic orbits and period orbits were obtained by Hamilton functions of the system, and the corresponding specific analytic expressions of different orbits were deduced. Based on the multiple scales method for nonlinear vibration analysis, the first approximation solutions and corresponding to steady state solutions of the 3 super-harmonic resonances were studied. The relations between different parameters were revealed clearly. Numerical analysis results show that material nonlinearity and temperature variation are critical factors influencing the vibration, which should not be neglected. In some conditions, the movement such as chaotic motion can be found in the system. In order to control the flexible manipulator effectively, parameters should be designed correctly to avoid the chaotic movement.
Pose error analysis of robot in three dimension
Ding Xilun, Zhou Lelai, Zhou Jun
2009, 35(2): 241-245.
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In terms of 5 parameters model as the kinematics model of robots, according to the transferring relationship of errors between the adjacent linkages, with the position and orientation modeling matrix method, the position and orientation error model of robot in three dimension was built, and the position and orientation error analysis program (software) based on C++ was developed. Upon a 6-DOF (degree of freedom) space photographic robot, the influence rule of the end-effector error of the robot caused by the parameter changes was simulated using this error analysis program, and an equivalence error curve picture of the robot was generated and discussed. Through the 5 parameters error model and the analysis software, the error distribution of the robot- s structure is obvious, convenient for the rational usage of robots or emendation for robots- structural errors. The research result provides a basic reference for the error compensation of robots.
Multiscale fyzzy-adaptive Kalman filtering methods for MEMS gyros random drift
Chen Diansheng, Shao Zhihao, Lei Xusheng, Wang Tianmiao
2009, 35(2): 246-250.
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A new time series method was proposed to construct the random drift model for the micro electro mechanical sensor (MEMS) gyro. Based on the wavelet multi scale analysis method, the gyro random drift data was decomposed to a series of scale gyro drift data with depth of 4 using bior1.5 wavelet, each scale signal was rebuilt and then constructed the corresponding multi scale time series models to reduce the overall predict error. Moreover, an adaptive Kalman filter algorithm was proposed to improve the compensation performance for the random drift noise. The noise variance was modified by using the fuzzy adaptive system which is based on the mean and variance margin of residual sequence. The effectiveness of the proposed method was proved by a series of experiments compared with multi scale analysis with simple Kalman filter (SKF). Each random item was reduced using Allan variance analysis.
Basic research on configuration of climbing worm robot
Wang Wei, Wang Kun, Li Dazhai, Zong Guanghua
2009, 35(2): 251-255.
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Two novel module climbing caterpillar kinematics models according to the vermicular motion of the pine caterpillar and inchworm were presented. The differences of two models were indicated after the analysis of the valid gaits and climbing safety of them. Although the pine caterpillar model with all active joints introduces the redundant actuating to its locomotion but it has higher security than the inchworm model because of its more valid gaits. Two prototypes following the above two models were respectively constructed from some newly developed real adhesion and actuation modules to testify the climbing abilities of two caterpillar-like robots. The experiments show the sideslip of the suckers on the pine caterpillar robot induced by the redundant actuating and the locomotion ability of the inchworm robot on vertical wall. Besides that, an unsymmetrical gait was adopted by the inchworm robot to improve its adhesion reliability on the wall.
Locomotion gait control algorithm for climbing worm robot
Li Dazhai, Wang Wei, Wang Yingying, Qi Jinghao
2009, 35(2): 256-260.
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A wall-climbing worm-like robot based on the bionics principle was designed and the structure feature of the climbing worm robot was analyzed. According to the structure and locomotion feature of the climbing worm robot and the bionics principle, the trapezoidal wave gait and triangular wave gait were proposed. Then the cyclic inhibitory central pattern generator (CPG) model and mutual inhibitory CPG model were adopted to control the climbing worm robot and a locomotion gait simulation based on CPG model was given. Furthermore, by combining the CPG output with the feedback signal from the sucker, the climbing worm robot realized the trapezoidal wave gait and triangular wave gait. Moreover, it was presented that real robot can successfully exhibit meandering movement by using controller output of the proposed architecture.
Optimal design for passive robot in rough terrain based on VCM
Liu Jinhua, Bi Shusheng, Sun Minglei, Pei Xu
2009, 35(2): 261-265.
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The mechanism with the characteristics of virtual center of motion (VCM) is one of the limited degree of freedom (DOF) mechanisms substantively. The VCM was employed in robots which were mobile on rough terrain for its special characteristics. The front mechanism was optimized through analyzing the relation of the VCM and the center of the front wheel． The static model of the robot was simplified for the character of VCM. According to the static analysis, the parameter and the position of the spring suspension on the front mechanism were optimized through minimizing the friction coefficient of the wheels. The ground contact of all wheels at any time was guaranteed by the spring. An optimized prototype was designed and manufactured. It is able to passively overcome obstacles of up to 2.1 times of its wheel diameter and can climb stairs with steps of over 1.27 times. The advance of the passive adaptation in rough terrain was shown in the contrastive experiments.

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