Applied Mechanics and Materials Vols. 16-19

Abstract: According to the pair transformation theory on mechanism derivation, the internal bevel gear meshing pair of nutation drive is replaced by rolling elements. In this manner, gear teeth are eliminated and the problem of manufacturing the interval bevel gear is solved completely. The method to generate new tooth profiles of nutation drive is put forward. Using this method, a novel nutation drive is presented. This system is made with a minimum number of parts, and can remain constant transmission ratio. In this paper, the problems such as tooth profile synthesis and kinematic analysis of the mechanism are studied. The formulae for calculating transmission ratio of the reducer are developed and theoretical profile equations of the stator and the rotor are obtained.

Abstract: In recent years, the demands on product performance are improving, particularly in the aviation; electronics, precision instruments and other fields, the accuracy and quality have become the most important. So lapping is getting increasingly importance with its high precision, good processing quality. In this paper, the processing parameters, which have effect on processing accuracy and efficiency in the process of planar lapping, have been analyzed emphatically. The effects on surface roughness of various processing parameters have also been investigated.

Abstract: A flexible remanufacturing system based on arc weld robot is established which consists of three subsystems: 3D laser measuring subsystem, modeling subsystem and off-line programming subsystem. The whole remanufacturing procedure consists of a several steps, such as work piece measuring, locating, modeling, welding program generating and surface depositing. The surfacing program consists of automatic delamination, automatic weld bead planning and welding parameter generation. The system can be easily employed to an automatic remanufacturing of work piece of various state of surface damage. Test remanufacture are carried on damaged plate, damaged column and worn axletree, and the results show the system is feasible.

Abstract: This paper takes one kind of 3-TPT Hybrid Machine Tools (HMT) as the object to study. It mainly analyzes the influence of the parallelogram mechanism as the restraining chain of machine on the posture error of movable platform. Firstly, on the basis of introducing the structure of HMT, the kinematics of the restraining chain of this machine is analyzed, and the kinematics equation of the restraining chain is established. Secondly, the influence of two kinds of factors including the shape error of parallelogram mechanism and the micro-rotation of Hooker joint around the axis of connecting rod is analyzed respectively, and the theoretical relationship expression is acquired between various errors influencing factor and the posture error of movable platform, thus the foundation for the theoretical error analysis of the HMT is laid.

Abstract: Considering the characteristics of dynamic alliance task scheduling, timed place Petri-net (TPPN)-based approach is proposed to model the task scheduling. On the basis of formal definition and transition rules of the TPPN, dynamic alliance manufacturing types are classified, and the TPPN model of each kind of manufacturing is provided. Then through analyzing time difference of each task, critical path in TPPN model is solved. Finally, State flow is used to simulate the TPPN model, and the simulation of a case demonstrates that the approach is feasible and effective.

Abstract: After the business model and the ontology meta-model of production workshops are analyzed and the business processes of the workshop are described formally, the upper ontologies are built on the basis of the business process, and are used to derive the domain ontologies in the workshops. Using SWRL to extend ontologies with rules overcomes the expressive limitation of ontologies. The system architecture of the manufacturing knowledge generation based on rules is put forward. Finally an example is used to explain the process of knowledge generation based on the rules.

Abstract: Cell formation which involves grouping similar parts into part families and the corresponding machines into machine cells is one of the key research issues for designing cellular manufacturing system. Functionally identical machines may vary in production performance. In the paper, processing cost is employed to differentiate the performance of machines, and a two-stage cell formation approach for manufacturing systems with multiple functionally identical machines is proposed. With this approach, parts are firstly clustered into part groups based on process similarity; secondly, machines are then assigned to part groups according to their performance to form manufacturing cells. A heuristic algorithm based on process similarity is presented for part group identification, and a mathematical model with the objective of minimizing the total processing cost is established. An example is employed to illustrate the benefit of the proposed approach and the results suggest that the proposed approach is feasible.

Abstract: Solve the flexible dynamic scheduling problem by using “dynamic management & static scheduling” method. Aim at the property of flexible Manufacturing systems, the dynamic scheduling methods are analyzed and a coding method based on working procedure is improved in this paper. Thus it can be efficiently solve the problem of multiple working routes selection under the active distribution principle. On the other hand, the self-adaptive gene is provided and the parameters of the genetic algorithm are defined. In such a solution, the scheduling is confirmed to be simple and efficient.

Abstract: Modern manufacturing industries are increasingly faced with international competition and fluctuating market conditions in the age of globalization. In striving to remain competitive, manufacturing industries must deliver products to customer at the lowest cost, at the best quality and in the minimum lead time. As a result, it becomes mandatory to design and implement the advance production planning and scheduling system that supports shorter product cycles despite more complex and specialized manufacturing processes. The advance production planning and scheduling system provides the leaner production strategies and real time information throughout the industry. This paper presents an appropriate Advance Production Planning and Scheduling Software System for a batch production aerospace manufacturing industry. The Software system receive the customer‘s order and perform material requirement planning using software. The software system sends procurement requisition to the procurement department for the materials which is not available in the store for manufacturing of parts. It issues release order to the store section for the issuance of material to the manufacturing shops. It also issues weekly and daily plan with production schedule to the manufacturing shops. It also issues work orders to the production shops for the manufacturing and assembly of the parts. On the completion of the product assembly, proper closing of the work orders has to be done and product may deliver to the warehouse for further handing over to the customers. In case of modification of order by the customer, the Software System will automatically update the relevant data.

Abstract: Based on the analysis of current state of aeroengine fault diagnosis, this paper proposes the design and implementation of a web-based fuzzy expert system called WFESAFD, which is focused on the monitoring and fuzzy fault diagnosis of aeroengine. The system architecture and its components, such as web interface layer, monitor, knowledge acquisition and management, integrated data base, reasoning mechanism and knowledge base are illustrated. The detail process of system implementation and practical applications of WFESAFD are presented to illustrate and prove the proposed system’s applicability. Running results show the feasibility and reliability of the framework, which will be helpful to integrate the aeroengine diagnosis knowledge, improve the diagnosis efficiency and decrease the aeroengine diagnosis cost remarkably.