Advanced Materials Research Vols. 118-120

Abstract: The design of the biped toy robot in this study, presents a brand new concept compared to that of the conventional mechanical biped robots on the market. These conventional mechanical products rely mainly on a large sole area to stabilize the wobbling movement during walking. In this design walking stability is not achieved by large sole areas, but by having more degrees of freedom and automatically shifting the center of gravity as the robot walks. A single motor is used to drive the biped toy robot trunk so that the center of gravity is automatically shifted to achieve walking stability. The two feet are driven by four connecting rods for striding and leg-lifting action. More particularly, an equal parallel crank mechanism is provided that uses a single motor to drive the connecting rods, thereby swinging the center of gravity of the toy robot in time with striding frequency. In addition, the concept of the zero moment point is utilized in the shifting of the center of gravity allowing the biped robot to lift its legs, change step, and move forward in balance. This study also discusses the use of the four connecting rods, and the shifting of the center of gravity of the robot, as an alternative to the servomotors commonly used in conventional robots which are bulky, expensive and hard to control.

Abstract: Establishing a general technical platform for the function-oriented design of point-contact tooth surfaces of spiral bevel and hypoid gears is an important and fundamental work. Based on the three-axis CNC bevel gear machine, a general mathematical model for the generated gear tooth surfaces of spiral bevel and hypoid gears is established. According to the principle and the method for the function-oriented design of point-contact tooth surfaces, the locus of spatial tooth contact points on the tooth surface is described on the axial plane of the gear, and then the formulae for the design with the generated gear are derived from the mathematical model. The mathematical model and the formulae can be used in the function-oriented design of point-contact tooth surfaces with the gear generated in different types on both the three-axis CNC bevel gear machine and the conventional cradle one. A theoretical method for the verification of point-contact tooth surfaces is proposed and the formulae for the verification are presented. And lastly an example is given to demonstrate the function-oriented design of point-contact tooth surfaces of the hypoid gear drive with the generated gear.

Abstract: The wear experimental project on load and sliding speed was instituted by the uniform design method, the wear properties of 38CrMoAlA alloy steel under dry friction were investigated on a vertical universal friction and wear tester, the worn surfaces of specimens were observed by scanning electron microscope (SEM). The wear life predication model of 38CrMoAlA alloy steel was established by multiple regression analysis, and the significance of influencing factors was carried out. The results showed that the distribution of experimental points chosen by uniform design method was in research range, and the experimental efficiency was evidently increased, and the experimental cycle was shortened. The wear mechanism of 38CrMoAlA alloy steel was primarily abrasive wear and adhesive wear. It is found that the wear life predication model was highly significant.

Abstract: Vacuum brazing of glass to Kovar alloy was carried out at 670~700°C using Cu-Ni-Sn-P brazing alloy. The holding time ranges from 5min to 30min. The shear stress was tested to evaluate the mechanical property of the vacuum brazed joints. The results showed the maximum shear stress was 11.6MPa when the brazing temperature was 680°C and holding time was 10min. In accordance with the welded structures, the finite element (FE) model of glass-to-metal brazed joints was established. As result, the shear tests on the lap joints in conjunction with FM analysis were used to optimize the glass-to-metal brazing technology. The above results provide the basis of design against damage and reliable estimation of glass-to-metal seals.

Abstract: A strategy other than forced decoupling or tearing to solve the problem in concurrent design process planning is produced. Twice-modeling concept is proposed by building an Information Flow Matrix (IFM) based on the influence of relationships between information flows during task execution. After re-constructing the IFM to determine the order levels of information flows, the provider-receiver relationship between tasks and information flows are used to instruct the planning of the key tasks. A design task is then decomposed according to the usage or supply of information flow. Adaptive subdivision of design tasks is realized based on synchronous mapping of Coded Design Structure Matrix (C-DSM) and IFM. Finally the whole design process planning is completed by the priority definition of the subtasks and a DSM based level generate algorithm. The proposed method is illustrated by an application to the vehicle overall design process planning. The “pseudo coupled” or “pseudo dependent” relationships are eliminated effectively without forced decoupling and the concurrency of the whole design process is improved obviously.

Abstract: Many previous researchers have shown design to be essentially the process of negotiating and resolving constraints. This has lead to a multitude of different design methods and approaches purely based on constraints; much of this work has concentrated on the late conceptual and embodiment phases of the design activity. The work presented in this paper has shown initial investigations into expanding these approaches to the earliest stages of the conceptual phase. The research has reviewed previous academic work, and the current approaches and understanding of designers working in the automotive domain. The findings of this research are presented and analysis given.

Abstract: Vibration test of the whole machine has become an important measure to solve vibration problem of NC machine tool, because it can evaluate anti-vibration performance and check the validity of vibration analysis. In the paper, on basis of confirming the vibration test contents for NC machine tool, the vibration test method and flow of the whole machine are proposed from the need of engineering, which include planning experiment instruments, confirming test contents, putting up test system, vibration test, analyzing experiment data etc. At last, taking a NC boring machine which is built by Shenyang machine tool group as study case, the whole machine vibration test is done. The practice indicates that the method is effectual.

Abstract: The key issue of FAHP application is how to derive fuzzy weights from fuzzy pairwise comparison matrix. The most of applications, however, were founding avoiding the use of sophisticated approaches such as fuzzy least squares method and using a simple extent analysis method to derive fuzzy weight from pairwise comparison matrix for the sake of simplicity. But the extent analysis method proves to be incorrect and may lead to a wrong decision result. So, this paper proposes a sound yet simple linear goal programming model to derive weights from pairwise fuzzy comparison matrix, which takes minimizing inconsistence degree of comparison matrix as objective and obtain a normalized weight vector finally. The proposed model is validated by an application to new product development scheme screening decision making.

Abstract: . Successful collaborative product development depends on the ability to effectively manage and share engineering knowledge and experience throughout the entire development process. This paper presents a distributed heterogeneous engineering knowledge management approach for the practice of collaborative product design. Firstly, a XTM based heterogeneous knowledge integration model in collaborative product design is proposed; Then, a knowledge management framework in collaborative design process is developed; Finally, a knowledge management system in collaborative design is constructed.

Abstract: In order to resolve the problems encountered in the process of forecasting the quantity of equipments demanded by aircraft’s support system during the design and development phase, including the difficulty to collect the input data of the existing forecast models and their imprecise and unauthentic output results, a model of was established to forecast the number of support equipments based on support activity flow described by functional flow diagrams. Firstly, the aircraft’s typical mission was analyzed and the quantity of operation and maintenance support activities happened in the duration of the mission was calculated on the basis of the typical mission’s data and aircraft’s reliability data. Secondly, the working hours and maximum number of the support equipments demanded by the support activities in the bottom of the functional flow diagrams was calculated and analyzed. Thirdly, an approach to sum the working hours and maximum quantity of the support equipments demanded by the support activities with logic relations in the same level of the functional flow diagrams was presented and with which the working hours and maximum number of support equipments demanded by the top-level support activity was achieved. Fourthly, the quantity of support equipments to be allocated in the support sites was calculated. At last, the proposed model was demonstrated via a practical case of aircraft, which proved that the model is corrective and effective.