• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.632-635
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• 2002

In this paper, a general procedure to determine machine tool errors from the on-machine measurement (OMM) data is described. First, a parameterized error model of a machine tool is illustrated by approximating error components as linear function of axis positions, and a modified error model is proposed which includes backlash effects. To determine the unknown model coefficient vectors of the forward and backward error model, an artifact with 8 cutes is made and calibrated on CMM. Then, lower-left and upper-right cube corners are measured with a touch-trigger probe mounted on the machine tool spindle. Measured error data are used to determine the coefficient vectors. The positioning errors in the XY plane at the fixed z position are simulated for the forward and backward error model.

• 한국정밀공학회지
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• 제11권6호
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• pp.117-126
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• 1994

This paper describes an application step of a $R^{-{\theta}}$ method which measures circular movements in machining centers. The detection of composite errors of circular movements and a high precision cutting method in machining centers were investigated by the analysis of data measured by $R^{\theta }$method which can detect the rotating angle and is applicable to variable measuring radius. When the error by squareness error and unbalance of position-loop-gain were mixed, the detection method of each error was proposed. Although the errors by squarenss error and backlash compensation were mixed, the errors by squareness error be detected. If the errors by unbalance of position-loop-gain and backlash compensation were mixed, the errors by unbalance of position-loop-gain could not detected. A high precision cutting mehod, which uses the NC program compensated by using feed-back data from error measured by the $R^{\theta }$method, was proposed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 D
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• pp.2684-2686
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• 2005

This paper presents design of nonlinear controller based on genetic-fuzzy algorithm. Motor system that is included at a humanoid robot has many nonlinear parameters such as saturation, backlash and so on. So, it is hard to control a humanoid robot because of these nonlinearities. Also, tracking following ability is also reduced by these nonlinearities. In this paper, fuzzy PID controller is proposed for reducing efficiency by saturation. At that time, genetic algorithm is supplied at making fuzzy rule in order to make optimal fuzzy PID controller. Also, disturbance observer is used to reduce the efficiency of backlash. All these processes are verified by simulation and experiment in the real humanoid robot.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2006년도 추계학술대회 발표 논문집
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• pp.178-183
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• 2006

Effect of coulomb friction and backlash on the single loop posit ion control has been studied for the precision position control. We studied and showed the limit cycle on the single loop system which used a ball screw that had the backlash. Also, We made an inner loop with a classical velocity and torque controller which was forcing the $i_d$ current to be zero by using a permanent-magnet synchronous motor and composed the outer loop with linear sensor for sensing a position of the loader. We have been shown a good result by using the dual loop through numerical simulation method.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.406-409
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• 1997

An economical 4-axis CNC controller employing step motors is designed and implemented in this paper. By using the inherent ability of holding position of the motor, the CNC controller uses open-loop control for removing trajectory error and for a simple hardware. Each drive of axis has an 8-bit microprocessor 89C52 and a PC controls the axes and pendant by means of RS232C serial communication. Backlash is also compensated at the axis controller. While compensating the backlash, the feed rate becomes zero in order to minimize trajectory error. The trajectories of 16ms interval are computed on PC and are sent to motor drives. In the drives, the trajectories are linearly interpolated for 2ms interval. The developed CNC does not require add-on specific motion card on PC. From the experimental results, the validity of the CNC controller based on step motor is proved.

• 대한기계학회논문집A
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• 제24권11호
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• pp.2713-2722
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• 2000

When designing a gear drive, designers should specify tolerances reasonably considering accuracy, cost, and manufacturing capability. In field design, however, designers mostly assign adequate tolerance without correlations between parts and assembly, resulting in iterative design dependent on experts know-how. In order to resolve this, the tolerance design system for a cylindrical gear drive is developed both to support tolerance design automation and to synthesize design processes of part and assembly tolerances. In this research, part tolerances are designed with the databases constructed by ISO, Ks, JIS and bearing catalogue, Assemble tolerance, that is, backlash tolerance is designed by synthesizing part design tolerances stochastically using the formulated assembly relations. This system can include part tolerance and fitting accuracy of shaft adn bearing in practical design. In addition, this system provides field-designers with a synthetic guideline for tolerance design of a gear drive.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.329.2-329
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• 2002

This paper presents an improved escalator dynamic model so as to reflect the experimental observation on the pseudo-resonance affected by load applied. The experimental evidence reveals that backlash of gearbox as well as sag of driving chain are most critical factors to the pseudo-resonance in escalators. The dynamic model effectively reflects vibration characteristics measured in real escalators with respect to different conditions of driving chain and the number of passengers. (omitted)

• 한국전자통신학회논문지
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• 제7권2호
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• pp.417-423
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• 2012

본 논문에서는 모터 설계에서 기존의 단일 모터를 사용한 구동 구조의 단점을 보완하고 중공형 관절의 장점을 활용할 수 있는 방안으로 다수의 모터를 이용한 관절 구성을 통해 높은 토크, 높은 정밀성, 낮은 백래쉬 구현 방법, 2차적인 안전장치 설계 및 적용 방법 등을 제시한다.

• 한국정밀공학회지
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• 제20권12호
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• pp.34-41
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• 2003

This paper suggests a methodology fur improving the machining accuracy by compensating for the machining errors based on on-machine measurement process. Probing errors and machine tool errors included in the measurement data were calibrated or compensated to obtain the actual machining errors. Machine tool errors were modeled in forward and backward directions according to the axis movement direction to consider the effects of backlash errors on the measurement data, and model parameters were determined by measuring a cube array artifact. A rectangular workpiece was machined and then measured with a touch probe as a verification experiment. Machining experiments showed that the machining errors were reduced to within the designated tolerance after compensating for the actual machining errors by modifying the original footpath for the next-step machining.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.650-653
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• 2002

In this paper, a methodology to assess machine tool errors quickly is suggested using a touch probe and a cube array artifact. Parameterized error models derived are expressed of model coefficient vectors and backlash errors to be determined. To determine the unknown model coefficient vectors, a cube array artifact is proposed. Considering CMM measurement data of cube vertex coordinates. error vectors for all axes ate obtained and used to complete the error model. Some simulation results show that the suggested error model can follow the true values within 10$\mu\textrm{m}$. To verify the error model, a circular part with two concentric circles is measured and simulated. The results show that the differences between CMM and OMM radius errors are smaller than 15$\mu\textrm{m}$.