Materials Science Forum Vols. 505-507

Abstract: The piezo-actuated stages are composed of the piezo-electric actuator and the positioning mechanism. The positioning accuracy of the piezo-actuated stage is limited due to hysteretic nonlinearity of the PEA and friction behavior of the positioning mechanism. To compensate this nonlinearity of piezoelectric actuator, a PI feedback control associated with feedforward compensating based on the hysteresis observer is proposed in this paper. Identifying its parameters is very important; so the genetic algorithm is studied to find the optimal parameters. To verify the feasibility of the proposed method, it is implemented on the precision positioning task of the piezo-actuated stage in the real-time control architecture.

Abstract: Dynamic MRR (material removal rate) modeling is constructed and optimum solution through Calculus of Variations in maximize the machining profit of an individual cutting tool under fixed tool life is introduced. The mathematical model is formulated by reverse experiments on an ECOCA PC-3807 CNC lathe, and the electronic circuit is developed using linear regression technique for virtual machining. The inaccuracy between actual and simulated voltage is assured to be within 2%. By introducing a real-world CNC (computerized numerical control) machining case from AirTAC into the virtual system, the simulated cutting forces are shown to promise the feasible applicability of the optimum MRR control. Additionally, the implementation of dynamic solution is experimentally performed on a proposed digital PC-based lathe system. The surface roughness of all machined work-pieces is found to not only stabilize as the tool consumed, but also accomplish the recognized standard for finish turning.

Abstract: Knowledge discovery in database (KDD) represents a new direction of data processing and knowledge innovation. Design is a knowledge-intensive process driven by various design objectives. Implicit knowledge acquisition is key and difficult for the intelligent design system applied to mechanical product design. In this study, the characteristic of implicit design knowledge and KDD are analyzed, a model for product design knowledge acquisition is set up, and the key techniques including the expression and application of domain knowledge and the methods of knowledge discovery are discussed. It is illustrated by an example that the method proposed can be used to obtain the engineering knowledge in design case effectively, and can promote the quality and intelligent standard of product design.

Abstract: This paper considers nonlinearly mixed integer tolerance allocation problems in which both tolerance and process selection are to be decided simultaneously so as to minimize the manufacturing cost. The tolerance allocation problem has been studied in the literature for decades, usually using mathematical programming or heuristic/metaheuristic optimization approaches. The difficulties encountered for both methodologies are the number of constraints and the difficulty of satisfying the constraints. A penalty-guided artificial immune algorithm is presented for solving such mixed integer tolerance allocation problems. Numerical examples indicate that the proposed artificial immune algorithms perform well for the tolerance allocation problem considered in this paper. In particular, as reported, solutions obtained by artificial immune algorithm are as well as or better than the previously best-known solutions.

Abstract: Methods of standard genetic algorithm (SGA) and adaptive genetic algorithm (AGA) are employed to improve performance of global cutting for an arbitrary closed region. Normal conditions and special types of the closed region are also analyzed and discussed by the area map. It appears that the presented GA frameworks are superior to the blind search algorithm (BSA) and are suitable for the special types of remaining closed space (RCS). By comparing three experimental results, it can be concluded that area efficiency and time reduction are trade-offs.

Abstract: This paper presents a predicted model of surface roughness of radial relief for resharpening end-mill. This model is constructed using a polynomial network. The major factors affecting grinding parameters are considered to be wheel spindle speed, feedrate, and grinding depth of cut. Experiments under specified conditions are deliberately designed and conducted to obtain the corresponding tested data for surface roughness that are used for training data of the proposed polynomial network. Consequently, a predicted model for surface roughness is established. Furthermore, a computer program in VB language is written based on this model. It can quickly calculate predicted values of surface roughness by simply inputting required cutting parameters. According to the experimental results, the developed polynomial network model shows high predicting capability on surface roughness of radial relief, and possesses promising potential in the application of predicting surface roughness in resharpening end-mill operation.

Abstract: This paper presented a digital servo driver that realizes an auto-tuning feedback and feedforward controller design using on-line parameters identification. Firstly, the variant inertia constant, damping constant and the disturbed load torque of the servo motor are estimated by the recursive least square (RLS) estimator, which is composed of an RLS estimator and a disturbance torque compensator. Furthermore, the auto-tuning algorithm of feedback and feedforward controller is realized according to the estimated parameters to match the tracking specification. The proposed auto-tuning digital servo controllers are evaluated and compared experimentally with a traditional controller on a microcomputer-controlled servo motor positioning system. The experimental results show that this auto-tuning digital servo system remarkably reduces the tracking error.

Abstract: This paper designs web-based USB 1-N wireless I/O modules embedded sequential controller. The controller consists of ARM-based core system, a set of USB 1-N wireless I/O data acquisition modules, and sequential control software. The ARM-based core system running Linux operation system forms the basic hardware/software foundation of the controller. The set of USB devices used as I/O interface (sensor and actuator) of thecontroller. With the use of RF chip, the USB I/O is cascaded by wireless 1-N channel such that multiple data acquisition modules can communicate with the controller by a USB port. The device driver of the USB set for the ARM-base Linux system is developed. The sequential control software is designed as client/server structure. The server-side program and client-side program communicate through the Internet. The server-side control program, mainly a PLC interpreter, is an application developed in C++ in the Linux system. The client-side control program is developed in Java and put under a web server of the controller such that the program can be easily deployed by network and run in remote computer. The client program is also used as GUI of the controller.