• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.453-458
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• 2000

Design of an in-process feedback control system has been studied for precision grinding. A grinding system consists of a grinding tool, a turn table and a disk-shaped workpiece on the table is taken as an object. A grinding process model has been deduced which gives some reasoning about the process errors. In the control system the tool position is actively controlled by an electro-magnetic actuator in-process. The ground error is feedback to compose a closed-loop control system and an optimal PID controller is applied. Some control performances such as transient response and disturbance such as transient response and disturbance attenuation have been examined, which convinces the effectiveness of the control. Some methods for implementation of the control. Some methods for implementation of the control have been suggested from a standpoint of practical application.

• 한국산업융합학회 논문집
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• 제20권1호
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• pp.34-48
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• 2017

This study proposes a new approach to control a trajectory control of vertical type articulated robot arm with six revolution joints by computed torque method for manufacturing process automation. The proposed control scheme takes advantage of the properties of the fuzzy controllers. The proposed method is suitable to control of the trajectory and path control in cartesian space for vertical type articulated robot manipulator for forging manufacturing process automation. The results is illustrated that the proposed fuzzy computed torque controller is more stable and robust than the conventional computed torque controller. This study is included with an analytical methodology of inverse kinematic computation for 6 DOF manipulators. And an intelligent PID based on feed forward fuzzy control structure is applied to control the working path control with disturbances caused by uncertainty parameters of the manipulator dynamic model. Lastly, the validity of proposed is verified by simulations and experiments.

• Journal of the Korean Wood Science and Technology
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• 제23권2호
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• pp.55-69
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• 1995

The primary objective of this research was to investigate optimum manufacturing condition of thin composite panels composed of sawdust, polyethylene film and polypropylene net. At the study the experiment was designed to make thin board in which sawdust offers effectiveness as core composing material, polyethylene as adhesive with added urea resin, and polypropylene as stiffness and flexibility in the composition panel. 100 types of thin composite panels were manufactured according to press-lam and mat-forming process of various hot pressing conditions(pressure, temperature and time). They were tested and compared with control boards on bending properties(MOR, MOE, SPL, WML), internal bond strength, thickness swelling, linear expansion and water absorption. At the same time the visual inspections of each types of panels were accomplished. The physical and mechanical properties of composite types passed by visual inspection were analyzed by Tukey's studentized range test. From the statistical analysis, the optimum manufacturing condition of thin composite panels were selected. Compared with two manufacturing processes, mat-forming process performed better than press-lam process in all tested properties. The optimum manufacturing conditions resulted from the experiment and statistical analysis were able to determine as following: the press temperature was shown the most good result at 130$^{\circ}C$ in mat forming process and 140$^{\circ}C$ press lam process, the press time 4 min in both processes, but the press pressure was 25-10kg/$cm^2$ in mat forming and 15k/$cm^2$ press lam process.

• 한국기계가공학회지
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• 제7권3호
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• pp.103-109
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• 2008

The work to raise the bridge plate by using two hydraulic cylinders is very dangerous when generating the unbalance state between cylinders. For solving this problem, one cylinder is forced to follow the trajectory of another cylinder instead of applying the same trajectory to two cylinders at once. In this paper, the control method for dynamic stable on lifting the bridge plate is proposed. The simulation model is derived by using commercial software, AMESim and MatLab/simulink. The PID controller is designed on one cylinder for following the reference trajectory and the adaptive controller is designed on another cylinder for tracking the displacement of one cylinder. The performance improvement is shown by comparing the simulation results through computer simulation.

• 한국기계가공학회지
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• 제10권4호
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• pp.102-108
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• 2011

LQG/LTR control scheme is applied to the two axes stage using piezoelectric actuator for tracking reference input and suppressing hysteresis effect in this paper. The plant is combined with an integrator to improve the tracking ability. LQG/LTR controller is designed by making desirable target filter loop remove all poles except for an integrator included in new design plant model and loop transfer recovery. Decoupler in the shape of FIR filter is added to remove the coupling effect between the two axes motion and so feedback control loop is designed independently for the each axis motion.

• 한국기계가공학회지
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• 제3권1호
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• pp.79-83
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• 2004

This study was how to control the mass flow controller in gas supplying system. The flow controller consists of piezoelectric material and sensor with heating wire. It is difficult to obtain accurate model, because MFC was composed of many parts, and the relationship between input and output of controller is nonlinear. The model for control was obtained by time constant and DC gain Based on this model, PID controller was applied to flow controller using DSP board. Also, the results were compared to controller using system identification.

• 한국레이저가공학회지
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• 제3권3호
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• pp.21-29
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• 2000

For the direct metal shape processing the powder feed device which is different from the widely used in rapid prototyping. is developed, The three dimensional object is shaped with the melting metal powder. The developed research has applied to rapid prototyping in ultraprecision for MEMS and medical science fields required of rapid manufacture of complex shape. The goal of this study make 3D model which has precision accuracy. Powder spreading apparatus has been more improved because that the control of powder spread is very important in layer manufacturing. It consists of the vibration motor, nozzle and tube which supplies various metal powder. This apparatus could control the spreading velocity that could control powder spreading thickness. Laser on/off switch was adapted because laser scanning velocity must be preserved constantly to prevent heat transformation of laser overheating. The error between sintered thickness md experimental one occurred by shrinkage in sintering melting process. The problem of heat transformation was solved by On/Off switching system.

• 한국기계가공학회지
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• 제11권6호
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• pp.88-93
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• 2012

In this study, Machining fine shaft was examined by Lathe. method is proposed to control the thrust force to 0. through relationship between the cutting depth and the thrust force in turning, fine-shaft of less than 0.1mm diameter in turning is confirmed experimentally. also we propose practical expression to control thrust force in turning Through to change the approach angle, optimal tool design would be possible in turning.

• 한국기계가공학회지
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• 제9권1호
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• pp.67-73
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• 2010

Finding sufficient supplies of clean energy for future is one of the society's most important challenges according to technologies. Alternative renewable energy source such as sun energy can be substituted for exceeding human energy need. The main factor affect to solar performance is a collective intensity. To enhance intensity, suitable equipment is a solar tracker. This paper presents design and evaluation of 1 layer polar motion control system for solar tracker suitable for building integrated system. To evaluation of tracking accuracy and adaptability, solar tracker with 64 links is implemented. In experimental results, the accuracy of tracking has under ${\pm}0.0287^{\circ}$ and the thickness has under 140mm.

• 대한안전경영과학회지
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• 제14권1호
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• pp.179-187
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• 2012

This paper presents a six sigma application case study for an automobile PCSV manufacturing process using rolled throughput yield improvement activity. Hidden factor and first yield concept is introduced and DMAIC procedure is implemented to maximize the first pass yield. The result of the six sigma project amounts to the reduction of failure cost of 0.1 billion won per year in the PCSV manufacturing process. This paper can benefit six sigma practitioners in some ways.