Application of fuzzy logic and regression analysis for modeling surface roughness in face milliing

The objective of this study is to examine the influence of machining parameters on surface finish in face milling. A new approach in modeling surface roughness which uses artificial intelligence tools is described in this paper. This paper focuses on developing empirical models using fuzzy logic and regression analysis. The values of surface roughness predicted by these models are then compared. The results showed that the proposed system can significantly increase the accuracy of the product profile when compared to the conventional approaches, like regression analysis. The results indicate that the fuzzy logic modeling technique can be effectively used for the prediction of surface roughness in dry machining.     

Adjustment of stochastic responses of typical cold forging systems

The stochastic nature of typical cold forging processes is assessed in this paper. Finite element computations have been applied to backward can extrusion, free upsetting, closed-die forging and forward rod extrusion in order to study the influence of scatter of the principal process input parameters on the dimensional accuracy of products and on the tool service life. Flow stress and mass of the workpiece have been varied in combination with tribological parameters to evaluate scatter of process responses for soft and stiff press. The results show that stochastic interactions differ radically for the four typical cold forging processes and that press stiffness has a significant influence on the stochastic relationships. For the closed-die upsetting it is demonstrated that statistical distributions of the input parameters can be adjusted in order to achieve reliable process. Here it is shown that bounds of operating windows defined by intersections between product tolerances and tool service life constraints are different for soft and stiff press. At the end of the paper an industrial example is provided to demonstrate how stochastic responses can be adjusted for production of the inner race.     

Fuzzy model-based optimal energy control during the electrical discharge machining

Neural Computing and Applications - This research aimed to describe a fuzzy optimal energy control strategy, so the electrical discharge machining (EDM) process can be optimized as a whole. The...     

High Precision Motion Control of Servo Drives

In this paper, we investigate the advantages and feasibility of motor control using very fast (in megahertz) switching in place of traditional amplifiers. We also propose integrated motion-control architecture based on discrete-event control approach to be implemented in digital logic at an equally high rate. A switching controller combines the current and motion feedback paths into a single loop. A model-based observer estimates the load torque. When compared to second-order controllers implemented with traditional amplifiers, the proposed design promises increased performance, better efficiency, and improved load estimation. Simple implementation makes concepts of switching control very attractive in motion-control systems like control of dc or ac servomotors. The control algorithm designed by the proposed approach can be easily implemented on field programmable gate array platforms.     

The Influence of Fracture Toughness on the Fine Blanking Tools Life

One of the most important operations in the manufacturing of fine blanking tools from HSS AISI M2, is vacuum heat treatment with uniform high-pressure gas quenching. The importance of optimal heat treatment is the possibility of making the optimum combination of the basic characteristics of fine blanking tools made from HSS for the given working part/fine blanking tool combination. Four different austenitization temperatures and four different tempering temperatures were chosen to produce the correct hardness balance, toughness, cutting properties and wear resistance in the finished tool. The result of the present investigation is important for the optimization of vacuum heat treatments of different tools made from HSS which are under tensile impact stress during exploitation. For them the optimal combination of hardness and fracture toughness are decisive.     

Control of manipulation robots interacting with dynamicenvironment: Implementation and experiments

In this paper, simulation experiments with different control laws are given, based on a new approach to solving the control tasks for robots in contact with the environment. The comparison of these control laws with the improved versions of the traditional hybrid control are also analyzed. The simulation experiments performed on a real-scale six-degrees-of-freedom industrial robot demonstrate the advantage of the new control concept and improved performances of the robot interacting with a dynamic environment. The tests conducted on industrial robot Manutec r3 are also presented     

Speed-sensorless sliding-mode torque control of an induction motor

Novel induction motor control optimizing both torque response and efficiency is proposed in the paper. The main contribution of the paper is a new structure of rotor flux observer aimed at the speed-sensorless operation of an induction machine servo drive at both low and high speed, where rapid speed changes can occur. The control differs from the conventional field-oriented control. Stator and rotor flux in stator fixed coordinates are controlled instead of the stator current components in rotor field coordinates i_sd and i_sq. In principle, the proposed method is based on driving the stator flux toward the reference stator flux vector defined by the input command, which are the reference torque and the reference rotor flux. The magnitude and orientation angle of the rotor flux of the induction motor are determined by the output of the closed-loop rotor flux observer based on sliding-mode control and Lyapunov theory. Simulations and experimental tests are provided to evaluate the consistency and performance of the proposed control technique