فهرست مطالب

  • Volume:7 Issue:1, 2018
  • تاریخ انتشار: 1397/10/05
  • تعداد عناوین: 6
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  • Payam Kheirkhahan Pages 5-19

    This paper presents a novel robust fractional PIλ controller design for flexible joint electrically driven robots. Because of using voltage control strategy, the proposed approach is free of problems arising from torque control strategy in the design and implementation. In fact, the motor's current includes the effects of nonlinearities and coupling in the robot manipulator. Therefore, cancellation of motor current by feedback linearization in voltage control strategy can cancel the highly nonlinear dynamics of manipulators. Thus, it can guarantee robustness of control system to both structured and unstructured uncertainties associated with robot dynamics. As a result, the proposed control is simple, fast response and superior to torque control approaches. The control method is verified by stability analysis. Simulations on a two-link actuated flexible-joint robot show the effectiveness of the proposed control approach. Compared with ordinary controller, the fractional type shows a better tracking performance.

    Keywords: Robust Fractional Control, Voltage Control Strategy, Electrically Driven Robots, Flexible-Joint Robots
  • Ahmad Reza Sabet, Hamid Montazerolghaem Pages 21-28

    Recently friction stir welding for manufacturing of welded tubes has been developed. Friction stir welding is a continuous solid state welding process in which a non-consumable rotating tool using severe plastic deformation Can join materials can be join materials. Commonly, a portion of a specially shaped rotating tool is plunged between metalsjoint cross section and adjacent faces of the joint. After entering the rotating tool on the weld, a relative movement between the rotating tool and the friction heating surface creates a plastic deformation zone around the submerged sections of the tool. The work piece will be heated during the friction stir welding, but the work piece temperature will not reach to the melting point. One of the major problems for manufacturing the thin cylindrical tube is related to low mechanical strength while the melting method such as laser is applied. In this research, it is reveals that the friction stir welding method can be a reasonabletechnique for manufacture of thin cylindrical parts. In this paper, an attempt was made to show thepossibility of frictional stir welding for manufacturing of thin cylindrical AA 6063aluminum parts. Various ranges of welding parameters include of rotation speed and welding speed are implemented to the thin thickness bent sheet i.e. 1.5 mm.By considering on obtained cylindrical tubes, it is found that the sound seem thin tube is achieved in rotational speed of 2500 rpm and welding speed of 4 mm/min respectively

    Keywords: Friction Stir Welding, Aluminum, Welding Parameters, Thin Tube
  • Marzieh Horry Najafabadi, Mehrdad Nikbakht , Ahmadreza Shekarchizadeh Pages 29-38

    The operational plan converts dream and imagination to a reality; in fact, it is anassured way to achieve organizational perspectives. The present study aimsto identify the performance indicators and to investigate the relationship between the operational performances of industrial manufacturing companies in terms of innovation, quality, productivity and efficiency. A researcher-made questionnaire has been used to evaluate operational performance and its indicators. This questionnaire has been allocated to the experts of the company which produces utility gas meters. Data analysis was performed by Pearson correlation and One Sample T-Test and the Amos software. The research findings show that operational performance emphasized on efficiency, productivity, effectiveness and future benefits of the organization and plays an important role in identification of innovation, quality, productivity and efficiency indicators and promotion of goals and improvement of organizational activities

    Keywords: Operational Performance, Innovation, Quality, Productivity, Efficiency, Utility Gas Meters
  • Seyed Ali Niknam , Keyhan Jabbari Pages 39-48

    This article reports the effects of various artificial aging methods and lubrication modes (dry, mist, wet) on the recorded cutting forces and chip morphology in drilling Al-Si-Mg (A356) cast alloys. In the course of this work, the work part sampled were as-received alloy (T0), solution heat-treated alloy (SHT) and then aged alloys at 155°C, 180°C, and 220°C (T4, T6, T61, T7), respectively. The significant effects of artificial aging the recorded cutting forces were noticed. Except minor cases under lower levels of feed rate, in general lower cutting forces were observed in A356-T0 and A356-T7 which are more brittle than other tested alloys. A direct relationship can be formulated among the microcracks on the free surfaces of the chips, brittleness and the recorded cutting forces. The use of MQL led to lower resulting cutting forces under similar cutting conditions. This can be related to less effect of thermo-mechanical stresses on the work part under MQL mode which tends to reduce the cutting forces.

    Keywords: Aluminum Alloys, Heat Treatment, Artificial Aging, Surface Quality, Cutting Force
  • Masoud Shahhosseini Pages 49-66

    In this note, we show that the impedance control strategy proposed in the paper is not feasible from practical implementation point of view. Next, a robust impedance controller is proposed for electrically driven robots using Fourier series (FS). The fact that robots' actuators have limited voltage is also considered in controller design procedure. In comparison with other impedance controllers using FS, the proposed controller results in fewer numbers of FS and consequently less computational load. These superiorities become more dominant when the manipulator degrees of freedom are increased. Simulation results on a Puma560 manipulator actuated by permanent magnet direct current electrical motors indicate the efficiency of proposed method.

    Keywords: Fourier Series, Impedance Control, Actuator Saturation, Electrically Driven Robot, Voltage Control Strategy
  • Mehdy Morady Gohareh , Saeid Azad Pages 67-78

    System engineering is one of the most powerful tools for comprehensive project management and control. This tool emphasized the life cycle of the projects, manages every single activity and helps manage the main elements of the project through a set of management and engineering processes. The goal of the current study is to use a system engineering approach in design phase in order or to meet operational needs. This study proposes a conceptual design process with system engineering approach which institutionalizes configuration management, risk management, change management, requirements management and integration during the entire design process. The results indicate a significant increase in meeting customer requirements and a positive increase in project quality. Finally, the indicators of design documents created using this approach are provided as an example.

    Keywords: System Engineering, Requirement Management, Integration, Product Design, Implementation Process, Parametric Design