Showing papers in "Journal of Machine Design in 2004"

Study on gear meshing efficiency under condition of elasto-hydrodynamic lubrication

Abstract: Based on the analysis and discussion of characteristics and law of gear engagement under condition of elasto-hydrodynamic, a calculation method on sliding and rolling work loss of standard spur gear transmission had been put forward, and the relationship of geometric parameters and overlapping coefficients of gear with sliding work loss was revealed. On the basis of utilizing geometric conversion and modification principle of spur and helical gears, the mathematical model for geometric parameters and modification of overlapping coefficients of gear was established, and the calculation method of sliding frictional coefficients under elasto-hydrodynamic lubrication state was introduced, thus let the calculation method of meshing efficiency of gears be more coinciding with the practical application.

Designing research of 3DOF humanoid hand with self-adaptation grasping

Abstract: The 3DOF humanoid hand used in humanoid figure robot, which has the ability of self-adaptation to the geometric features of object being grasped was designed. On the basis of accomplishing the design of finger mechanism with the ability of self-adaptation grasping, the movement coupling relations among every joints of this finger mechanism were analyzed. Further more, the correctness of transmission system of the designed human hand mechanism and the feasibility of self-adaptation grasping were verified through virtual prototyping technique. Finally, the targets for measuring the grasping ability of humanoid hand were put forward and the grasping ability of the designed humanoid hand was analyzed. All results indicate that the finger mechanism is reasonable and practical; the humanoid hand being designed and accomplished has achieved the requests of design.

Analytical model of accuracy probability for linkages with clearances

Abstract: By the use of matrix and theory of stochastic process, the probabilistic model of motion accuracy for linkages with clearances was established. This model possesses important guiding significance on the analysis and synthesis of reliability of mechanisms containing clearances.

Machinery product design based on KBE

Abstract: The Knowledge Baded Engineering(KBE) techniques and its application method were introduced. UG/Knowledge Fusion technique is a high-leceled technology integrating KBE techniques with UG system. It sidcussed knowledge fusion technology, its key techniques are knowledge representation, knowledge utilization and knowledge actuistion. An applied example was presented by taking the design of an automobile wyeel hub as an example.

Research on mechanism velocity and manipulability measures of force direction of dual armed robot

Abstract: On the basis of manipulability ellipsoid of mechanism velocity and force, the mechanism velocity and the directional manipulability measures of force of dual armed robot were defined. Taking the manipulability measures of direction as the function of target, the optimization method on mechanism's optimal transmission velocity, optimal direction of force transmission and optimal manipulative configuration was presented. The result showed that the force transmission property of dual armed mechanism is better than that of single armed mechanism.

Summary on the research of designing method for mass customization oriented product family

Abstract: Product family design is the key and core of mass customization design. A classified summing-up has been carried out for currently existed multi-methods of mass customization oriented product family design. An exposition has been made emphatically upon methods of product family design based on modularization and adjustable variables, which includes method of product family systematic architecture (PFA), robust concept exploratory method (RCEM), product platform concept exploratory method (PPECM) and variant based product desk method (VBPDM) etc. Taking these as the base the deficiency and developing trend of the present product family design was analyzed.

A new kind of parallel earthquake simulation platform with redundance actuation

Abstract: A new kind of parallel simulation platform with redundance actuation has been put forward. There is one or two driving interface modules installed separately in horizontal direction, and there are three driving interface modules with attached counterweight in vertical direction. Every driving interface module could equally be driven by one or two ball leading screws. Whenever two leading screws are used for driving, the input unit is in partial parallel state and being transformed into a unitary input of the system by means of a force balancing mechanism. Utilizing this platform, an earthquake simulation platform with 8 inputs and 6 outputs was constituted. It heightened life span of the screws to 18 times and 8 times separately in vertical and horizontal directions, thus a feasible channel was provided for the earthquake simulation platform to make use of an actuation of electro-mechanical system.

Research on stress analysis and contacting edge effect for interference fit joint of hub

Abstract: A detailed analysis on interference fit of hub was carried out by means of elastic mechanics and finite element method, in view of the above, the shortcomings of elastic mechanics method and the advantages of finite element method have been pointed out. Finite element method could not only obtain all the same stress of interference fit joint under ideal model as that obtained with elastic mechanics method, but also could analyze the contacting edge effect-edge stress concentration caused by contact, which could not be solved by elastic mechanics. Owing to considering the existence of stress concentration, to carry out design and check on interference fit joint of hub by the use of finite element method are more tally with the actual situation, thus more reasonable.

Research on elastic dynamic analysis and test for Diamond mechanism

Abstract: The elastic dynamic model of Diamond parallel manipulator was established by the use of KED (Kineto-Elastodynamic-Analysis). Two points of improvement were made in the establishment course of dynamics equation. (1) On account of the big influence to the rigidity on the plane of the mechanism affected by linking motor and reducer of driving arm, therefore a spring unit was added at the linking place of motor and driving arm, at this moment a tortile elastic displacement was added at the node point of hinge. (2) Let the moving platform and support structure in the parallel manipulator be treated as rigid body, and mutual harmonization of elastic unit with rigid body unit was being considered during the establishing course of dynamic model. A test upon the inherent frequency of this mechanism has been carried out at the same time. The result shows a good coincidence between the result of theoretical computation and the value of test, and the rationality and correctness of theoretical computation were verified.

Fuzzy reliability optimal design of cylindrical spiral compression spring based on genetic algorithm

Abstract: Aiming at the limitations of traditional optimization design and by means of applying fuzzy design theory and reliability design theory, this paper established a mathematical model of fuzzy reliability optimization design for springs and carried out optimization on it by the use of genetic algorithm. It is indicated by experiment that the genetic algorithm possesses fairly good applicable prospects on the respects of optimization design for springs.

Application of a modified Craig-Bampton method in dynamics modeling of multi-body system

Abstract: With the aid of Craig-Bampton modality synthetic method to carry out modification and being applied to describe elastic deformation upon flexible multi-body system such as space laboratory, flexible mechanical arm and so on Let the modality synthetic method be combined with the commonly used hybrid coordinative method in multi-body system modeling, so as to suit the coupling of rigid-body movement with elastic movement, which could reflect the dynamic characteristics of the system all the better With the combination of ADAMS, ANSYS software, this method can be used to carrying out the computer simulation analysis on the flexible multi-body system, and proceed to conduct the optimization design and so on

Green circulation economy and green design

Abstract: By means of analyzing the mutual effects between economic system and resources-environment system and the inside of economic system, the concept of green circular economy was expounded. It has been pointed out that the green circular economy is a basis of sustainable existence and development of humankind, and the design-manufacturing industry of green product and the green retrieval remanufacturing industry are the two most important links in green circular economic system, whether or not these two links could develop synchronously in coordination is the key of success or failure of sustainable development strategy.

Reliability model of fractional-ordered system

Abstract: The failure extent of a component is a continuous random variable between 0 and 1. And the failure extent of a system is the function of failure extent of its component, which is also a continuous function. Letting a discretization of the failure extent variable of component and of the failure extent function of system be carried out respectively, using the discretevariable to replace the failure extent variable of component and utilizing the decision table to replace the failure extent function of the system and carrying out an extension on document [1],the reliability model of fractional-ordered system, which is applicable for both linear and nonlinear accumulated failure system, is established. The employing method of this theoretical model is explained by a calculation example, and the correctness of this method is verified by the use of linear accumulative failure system.

Study on contacting strength of fewer teethed gear transmission

Abstract: Aimed at the meshing characteristics of fewer teethed involute gear pairs, the calculation point tally with the actual stress was found, and from this the empirical formulae were established for the calculation of contacting stress. The synthesized rolling speed and the influence of relative sliding coefficient of tooth surface were counted quantitatively in the formulae. Engineering practice showed that the result of calculation was reliable.

Approach to knowledge expression and its application in mechanical engineering design

Abstract: Knowledge expression is an important researching content of knowledge engineering and a foundation for carrying out knowledge deduction. Knowledge expression has many methods of different forms, different expression methods all have their own aiming and limitation, and different knowledge expression mode can be adopted for knowledge of the same field. The general method of knowledge expression has been simply introduced, and a synthetic evaluation was carried out upon their strong and weak points. At the same time, the choice and application of some commonly used expression methods were illustrated by examples. And the application of integrated expression of knowledge was explained in further steps.

New typed combination mechanism of linking rod and cam

Abstract: A kind of linking rod and cam combination mechanism, which could achieve a transmission of stable drive ratio, has been innovated. The transmission principle and calculation of drive ratio of this mechanism was analyzed. The mathematical equations of theoretical contour of cam and its tangent line and normal line were derived. Coordinates value of intersection point of common normal at each high paired contacting point were found by the use of analytical method, and the concept of pitch circle was presented. The expression of pressure angle of an arbitrary point on the theoretical contour of cam was established, and the moment relationship of driving and driven components was deduced. A kind of new typed linking rod and cam reducer was successfully developed based on this kind of mechanism.

Study on model of mechanism collaboration innovative design based on case-based reasoning

Abstract: Mechanism design is a designing process mostly full of innovations. Combining with techniques of case-reasoning, collaborative technology of computer network and principles of mechanism innovation, the model of mechanism collaboration innovative design based on case reasoning was put forward. The overall constitution of this model was introduced, and an explanation was made upon its key technology: case based reasoning technique, scheme evaluation system, data processing technique and technique of mechanism motion imitation. A new train of thought has been put forward for the realization of mechanism innovative design.

Analysis and calculation on dynamic characteristics of Geislinger coupling

Abstract: While bearing a fluctuate torque, the stiffness and damping of Geislinger coupling varies in pace with the variation of vibration frequency. The dynamic stiffness will cause natural frequency of the system to produce offset. The amount of offset has a bearing on the characteristic frequency of coupling and the natural frequency of original system. Through the development of state space, let the varying parametric equation of dynamic characteristics be transformed into constant coefficient equation, the solution is made within a space of 2n dimension, and the decoupling of equation is accomplished. The calculation showed that the amount of calculation of this method is smaller than those of the traditional iteration method.

Interference judging criterion of Hook joint and research on its optimal designing method

Abstract: Taking the Hook joint, usually being adopted in engineering, to be constituted by two identical straight prism typed hinge frame as the object of study, a set of mathematical formulae is used to judge whether the interference would happen or not while the hinge frame is having a relative movement under relations of various kinds of dimensions, and the verification of a virtual prototype has been obtained. Based on the judging criterion a kind of new method on the optimal design of Hook joint has been put forward as well.

Kinematical error analysis of modularized flexible-arm space robot

Abstract: A kind of comprehensive error analysis model of modularized flexible-arm robot was established. It merges together organically the kinematic errors caused by reducer for transmitting mainly the motion and that caused by elastic deformation of flexible-arm for the first time. The methods of reducing error and enhancing positioning accuracy of robot's extremity were discussed.

Application and development of CAD/CAM technology in the rapid formation of false tooth

Abstract: Computer aided design and manufacture technology of false tooth is a result of combination of advanced manufacturing technique and stomatological medicine. Every items of technology of foundation unit and systematic integration was analyzed on the layer of design and manufacture technology. It includes collection of primitive information, establishment of database, data processing, techniques of NC machining and equipment etc.. And the direction of research for further development of CAD/CAM system of false tooth was pointed out.

Deformation calculation and modality analysis on Y-axial beam of the robot used for line-heated forming of hull outer steel plate

Abstract: The finite element statics analysis and modality analysis have been carried out on an important component -Y-axial beam of the robot used for line-heated forming of hull outer steel plate By adopting the structural unit with 3D 10-node tetrahedron to compute the deformation of Y-axial beam under various typical working conditions, and pick up the law of deformation Taking this as a base, modality analysis was carried out on the Y-axial beam; the inherent frequency of former five orders and the vibration modality at places of corresponding frequency were solved The feasibility of its designing structure was verified, simultaneously a theoretical basis was provided as well for the follow-up analysis of machining accuracy and error compensation

Topological optimization design for flexible structure

Abstract: Problems on characteristics of flexibility structure, basic principle and method of topological optimization design, present situation of study and development at home and abroad and applications in engineering design etc. were discussed. Finally, the direction of development of topological optimization design for flexible structure, the problems need to be solved and the possible resolution scheme etc was set out as well.

Fuzzy reliability design of gear strength based on entropy theory

Abstract: Aimed at the difficult problem for determining the characteristic value of subordinate function in fuzzy reliability design, the theory of entropy was introduced in this article Under the premise of not completely depending the experience, the numeric calculation on fuzzy degree of gear reliability was carried out The relationship between characteristic value and reliability of subordinate function was described quantitatively, thus a new method for fuzzy reliability design of machinery was provided And an applicative typical example was attached

Simultaneous design of structure and control for a heavy loaded and high speed mechanical arm

Abstract: The working principle of mechanical arm was drew up, the dynamics equation of mechanical arm being controlled was established, the gain of PD controller was designed by the use of optimized algorithm, and the rigid body dynamics response of mechanical arm under different angles was calculated. In order to determine reasonable dimensions of mechanical arm, the elastic dynamics equation of mechanical arm was established by applying the method of finite element, the elastic dynamic response of mechanical arm under different sectional dimensions was solved, and the elastic vibration of mechanical arm was evaluated. It is verified through practice that the designing scheme of mechanical structure and control satisfies the requirement of design.

Dynamics analytical model of 6-dof industrial robot containing closed chain

Abstract: A kind of method of establishing the dynamics analytical model for close-chained industrial robot was established. Let the moving pairs of certain non-driving joint in the closed chain be disassembled and its motion relationship be substituted by constraint equations, thus formed an equivalent open chained system with additional constraint. Afterwards, the explicit formed dynamics equation was derived on the base of Kane dynamics equation. While deriving the analytical model, let partial variables be processed as symbolic amounts, and others be processed as numeric amounts, in this way the numeric-symbolic expressions for matrices elements of each dynamics model were obtained. Finally, a living calculation example was presented.

Shearing mechanism design of two mutually twisted flat screw wires

Abstract: The shearing work of two mutually twisted flat screw wires is a key link in the design of rhombic metal mesh weaving machines. At here, based upon designing idea of the shearing planes of left and right two shears are at ±45°with respect to main transmission plane and the combination with changeable structure, the shearing mechanism of two mutually twisted flat screw wires was designed. This kind of shearing mechanism possesses force-magnifying function, and the comparatively larger relative error of flat screw wire will not affect the shearing work.

Optimization design for robustness of linkages

Abstract: Taking the designing variables as the random variables, the mathematic model of optimal design for robustness of linkages was established, and by taking a four-bar linkage as an example, an explanation has been carried out. A contrast was made between the result of traditional deterministic optimal design and the result of robustic optimal design.

Research on the grinding apparatus for glass micropipette of manipulation

Abstract: The high efficiency grinding of glass micropipette can be realized by adopting the resin-bonded diamond grinding plate. The spindle supporting structure of micropipette grinding apparatus eliminated the influence upon the end wobble of grinding plate affected by motor. By adopting the microscope and CCD photographic system the adjustment of pipette and feeding process of grinding are observed directly. Reasonable range of speed regulation of pipette grinding apparatus and allowable value of wobble amount are determined by means of test.

Study on virtual design of the parallel indexing cam mechanism

Abstract: The surface formation characteristics of planar conjugated indexing cam were analyzed systematically, and the general mathematic model and equations suitable for various kinds of parallel indexing mechanism were established. Taking these as basis, the problems of solid modeling method for parallel indexing cam and of virtual design for this kinds of product have been approached. And taking the Solid Edge software as a platform, the application program was worked out, and a large number of calculations of living examples were carried out. The solid modeling method being advanced may lay a foundation for the deep study on virtual design problems of this kind of conjugated indexing cam product.